HRAS; Harvey rat sarcoma viral oncogene homolog (11p15.5)

Gene Summary

Gene:HRAS; Harvey rat sarcoma viral oncogene homolog
Summary:This gene belongs to the Ras oncogene family, whose members are related to the transforming genes of mammalian sarcoma retroviruses. The products encoded by these genes function in signal transduction pathways. These proteins can bind GTP and GDP, and they have intrinsic GTPase activity. This protein undergoes a continuous cycle of de- and re-palmitoylation, which regulates its rapid exchange between the plasma membrane and the Golgi apparatus. Mutations in this gene cause Costello syndrome, a disease characterized by increased growth at the prenatal stage, growth deficiency at the postnatal stage, predisposition to tumor formation, mental retardation, skin and musculoskeletal abnormalities, distinctive facial appearance and cardiovascular abnormalities. Defects in this gene are implicated in a variety of cancers, including bladder cancer, follicular thyroid cancer, and oral squamous cell carcinoma. Multiple transcript variants, which encode different isoforms, have been identified for this gene. [provided by RefSeq, Jul 2008]
Databases:OMIM, VEGA, HGNC, Ensembl, GeneCard, Gene
Protein:GTPase HRas
Updated:14 December, 2014


What does this gene/protein do?
Show (51)


What pathways are this gene/protein implicaed in?
- Angiotensin II mediated activation of JNK Pathway via Pyk2 dependent signaling BIOCARTA
- Aspirin Blocks Signaling Pathway Involved in Platelet Activation BIOCARTA
- BCR Signaling Pathway BIOCARTA
- Bioactive Peptide Induced Signaling Pathway BIOCARTA
- Cadmium induces DNA synthesis and proliferation in macrophages BIOCARTA
- Calcium Signaling by HBx of Hepatitis B virus BIOCARTA
- CCR3 signaling in Eosinophils BIOCARTA
- CXCR4 Signaling Pathway BIOCARTA
- EGF Signaling Pathway BIOCARTA
- EPO Signaling Pathway BIOCARTA
- Erk and PI-3 Kinase Are Necessary for Collagen Binding in Corneal Epithelia BIOCARTA
- Erk1/Erk2 Mapk Signaling pathway BIOCARTA
- Fc Epsilon Receptor I Signaling in Mast Cells BIOCARTA
- fMLP induced chemokine gene expression in HMC-1 cells BIOCARTA
- Growth Hormone Signaling Pathway BIOCARTA
- How Progesterone Initiates the Oocyte Maturation BIOCARTA
- IGF-1 Signaling Pathway BIOCARTA
- IL 2 signaling pathway BIOCARTA
- IL 3 signaling pathway BIOCARTA
- IL 6 signaling pathway BIOCARTA
- IL-2 Receptor Beta Chain in T cell Activation BIOCARTA
- Influence of Ras and Rho proteins on G1 to S Transition BIOCARTA
- Inhibition of Cellular Proliferation by Gleevec BIOCARTA
- Inhibition of Matrix Metalloproteinases BIOCARTA
- Insulin Signaling Pathway BIOCARTA
- Integrin Signaling Pathway BIOCARTA
- Keratinocyte Differentiation BIOCARTA
- Links between Pyk2 and Map Kinases BIOCARTA
- MAPKinase Signaling Pathway BIOCARTA
- mCalpain and friends in Cell motility BIOCARTA
- METS affect on Macrophage Differentiation BIOCARTA
- Multiple antiapoptotic pathways from IGF-1R signaling lead to BAD phosphorylation BIOCARTA
- Nerve growth factor pathway (NGF) BIOCARTA
- NFAT and Hypertrophy of the heart (Transcription in the broken heart) BIOCARTA
- p38 MAPK Signaling Pathway BIOCARTA
- PDGF Signaling Pathway BIOCARTA
- Phosphorylation of MEK1 by cdk5/p35 down regulates the MAP kinase pathway BIOCARTA
- Ras Signaling Pathway BIOCARTA
- Regulation of Splicing through Sam68 BIOCARTA
- Regulation of transcriptional activity by PML BIOCARTA
- Role of EGF Receptor Transactivation by GPCRs in Cardiac Hypertrophy BIOCARTA
- Role of ERBB2 in Signal Transduction and Oncology BIOCARTA
- Role of Erk5 in Neuronal Survival BIOCARTA
- Role of MAL in Rho-Mediated Activation of SRF BIOCARTA
- Roles of BIOCARTA
- Signaling of Hepatocyte Growth Factor Receptor BIOCARTA
- Signaling Pathway from G-Protein Families BIOCARTA
- Sprouty regulation of tyrosine kinase signals BIOCARTA
- T Cell Receptor Signaling Pathway BIOCARTA
- The IGF-1 Receptor and Longevity BIOCARTA
- TPO Signaling Pathway BIOCARTA
- Transcription factor CREB and its extracellular signals BIOCARTA
- Trefoil Factors Initiate Mucosal Healing BIOCARTA
- Trka Receptor Signaling Pathway BIOCARTA
- VEGF, Hypoxia, and Angiogenesis BIOCARTA
- Axon guidance KEGG
- B cell receptor signaling pathway KEGG
- Fc epsilon RI signaling pathway KEGG
- Focal adhesion KEGG
- Gap junction KEGG
- GnRH signaling pathway KEGG
- Insulin signaling pathway KEGG
- Long-term depression KEGG
- Long-term potentiation KEGG
- MAPK signaling pathway KEGG
- Natural killer cell mediated cytotoxicity KEGG
- Regulation of actin cytoskeleton KEGG
- T cell receptor signaling pathway KEGG
- Tight junction KEGG
- VEGF signaling pathway KEGG
Data from KEGG and BioCarta [BIOCARTA terms] via CGAP

Cancer Overview

Research Indicators

Publications Per Year (1989-2014)
Graph generated 14 December 2014 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

  • Tissue Fixation
  • Proto-Oncogene Proteins
  • Childhood Cancer
  • BRAF
  • DNA Sequence Analysis
  • Neoplastic Cell Transformation
  • Genetic Predisposition
  • RAS Genes
  • Eye Cancer
  • Virus Replication
  • Phosphatidylinositol 3-Kinases
  • Transcription
  • Risk Factors
  • Cancer Gene Expression Regulation
  • Melanoma
  • Cell Proliferation
  • RHOB
  • Translocation
  • Squamous Cell Carcinoma
  • Genotype
  • Adolescents
  • Polymerase Chain Reaction
  • Point Mutation
  • bcl-X Protein
  • Chromosome 11
  • Transport Vesicles
  • Uveal Neoplasms
  • Disease Progression
  • Apoptosis
  • Cancer DNA
  • DNA Mutational Analysis
  • Messenger RNA
  • Breast Cancer
  • Immunohistochemistry
  • Skin Cancer
  • Mutation
  • ras GTPase-Activating Proteins
  • Urethane
  • Exons
  • gamma-Crystallins
  • Gene Expression Profiling
Tag cloud generated 14 December, 2014 using data from PubMed, MeSH and CancerIndex

Notable (4)

Scope includes mutations and abnormal protein expression.

Entity Topic PubMed Papers
Breast CancerHRAS and Breast Cancer View Publications63
Skin CancerHRAS and Skin Cancer View Publications60
MelanomaHRAS and Melanoma View Publications41
Eye CancerHRAS and Uveal Neoplasms View Publications2

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Related Links

Latest Publications: HRAS (cancer-related)

McDaniel AS, Zhai Y, Cho KR, et al.
HRAS mutations are frequent in inverted urothelial neoplasms.
Hum Pathol. 2014; 45(9):1957-65 [PubMed] Article available free on PMC after 01/03/2015 Related Publications
Inverted urothelial papilloma (IUP) is an uncommon neoplasm of the urinary bladder with distinct morphologic features. Studies regarding the role of human papillomavirus (HPV) in the etiology of IUP have provided conflicting evidence of HPV infection. In addition, little is known regarding the molecular alterations present in IUP or other urothelial neoplasms, which might demonstrate inverted growth pattern like low-grade or high-grade urothelial carcinoma (UCA). Here, we evaluated for the presence of common driving somatic mutations and HPV within a cohort of IUPs, (n = 7) noninvasive low-grade papillary UCAs with inverted growth pattern (n = 5), and noninvasive high-grade papillary UCAs with inverted growth pattern (n = 8). HPV was not detected in any case of IUP or inverted UCA by either in situ hybridization or by polymerase chain reaction. Next-generation sequencing identified recurrent mutations in HRAS (Q61R) in 3 of 5 IUPs, described for the first time in this neoplasm. Additional mutations of Ras pathway members were detected including HRAS, KRAS, and BRAF. The presence of Ras pathway member mutations at a relatively high rate suggests this pathway may contribute to pathogenesis of inverted urothelial neoplasms. In addition, we did not find any evidence supporting a role for HPV in the etiology of IUP.

Related: Transitional Cell Cancer of the Renal Pelvis and Ureter Bladder Cancer Bladder Cancer - Molecular Biology

Lee TH, Chennakrishnaiah S, Audemard E, et al.
Oncogenic ras-driven cancer cell vesiculation leads to emission of double-stranded DNA capable of interacting with target cells.
Biochem Biophys Res Commun. 2014; 451(2):295-301 [PubMed] Related Publications
Cell free DNA is often regarded as a source of genetic cancer biomarkers, but the related mechanisms of DNA release, composition and biological activity remain unclear. Here we show that rat epithelial cell transformation by the human H-ras oncogene leads to an increase in production of small, exosomal-like extracellular vesicles by viable cancer cells. These EVs contain chromatin-associated double-stranded DNA fragments covering the entire host genome, including full-length H-ras. Oncogenic N-ras and SV40LT sequences were also found in EVs emitted from spontaneous mouse brain tumor cells. Disruption of acidic sphingomyelinase and the p53/Rb pathway did not block emission of EV-related oncogenic DNA. Exposure of non-transformed RAT-1 cells to EVs containing mutant H-ras DNA led to the uptake and retention of this material for an extended (30days) but transient period of time, and stimulated cell proliferation. Thus, our study suggests that H-ras-mediated transformation stimulates vesicular emission of this histone-bound oncogene, which may interact with non-transformed cells.

Milinkovic VP, Skender Gazibara MK, Manojlovic Gacic EM, et al.
The impact of TP53 and RAS mutations on cerebellar glioblastomas.
Exp Mol Pathol. 2014; 97(2):202-7 [PubMed] Related Publications
Cerebellar glioblastoma (cGBM) is a rare, inadequately characterized disease, without detailed information on its molecular basis. This is the first report analyzing both TP53 and RAS alterations in cGBM. TP53 mutations were detected in more than half of the samples from our cohort, mainly in hotspot codons. There were no activating mutations in hotspot codons 12/13 and 61 of KRAS and HRAS genes in cGBM samples but we detected alterations in other parts of exons 2 and 3 of these genes, including premature induction of STOP codon. This mutation was present in 3 out of 5 patients. High incidence of RAS mutations, as well as significantly longer survival of cGBM patients compared to those with supratentorial GBM suggest that cGBM may have different mechanisms of occurrence. Our results suggest that inactivation of TP53 and RAS may play an important role in the progression of cerebellar GBM.

Related: TP53 KRAS gene

Cogoi S, Shchekotikhin AE, Xodo LE
HRAS is silenced by two neighboring G-quadruplexes and activated by MAZ, a zinc-finger transcription factor with DNA unfolding property.
Nucleic Acids Res. 2014; 42(13):8379-88 [PubMed] Article available free on PMC after 01/03/2015 Related Publications
The HRAS promoter contains immediately upstream of the transcription start site two neighboring G-elements, each capable of folding into a G-quadruplex structure. We have previously found that these G-quadruplexes bind to the zinc-finger transcription factors MAZ and Sp1. In the present study we have examined the interaction between the HRAS promoter and MAZ, demonstrating for the first time that the protein unfolds the G-quadruplex structures. We also demonstrate that MAZ-GST, in the presence of the complementary strands, promotes a rapid transformation of the two HRAS quadruplexes into duplexes. By a mutational analysis of the HRAS G-elements, we dissected the MAZ-binding sites from the quadruplex-forming motifs, finding that the two neighboring G-quadruplexes bring about a dramatic repression of transcription, in a synergistic manner. We also discovered that the two G-quadruplexes are strong targets for small anticancer molecules. We found that a cell-penetrating anthratiophenedione (ATPD-1), which binds tightly to the G-quadruplexes (ΔT > 15°C), promotes the total extinction of HRAS transcription. In contrast, when one of the two G-quadruplexes was abrogated by point mutations, ATPD-1 repressed transcription by only 50%. Our study provides relevant information for the rationale design of targeted therapy drugs specific for the HRAS oncogene.

Related: Bladder Cancer Bladder Cancer - Molecular Biology

Giordano TJ, Beaudenon-Huibregtse S, Shinde R, et al.
Molecular testing for oncogenic gene mutations in thyroid lesions: a case-control validation study in 413 postsurgical specimens.
Hum Pathol. 2014; 45(7):1339-47 [PubMed] Related Publications
Molecular testing for oncogenic gene alterations provides clinically actionable information essential for the optimal management of follicular cell thyroid cancer. We aimed to establish the distribution and frequency of common oncogenic gene mutations and chromosomal rearrangements in a comprehensive set of benign and malignant thyroid lesions. A case-control study was conducted in 413 surgical cases comprising 17 distinct histopathologic categories, 244 malignant, 169 benign, and 304 double-blinded specimens. Seventeen alterations of BRAF, HRAS, KRAS, NRAS, PAX8, and RET genes were evaluated using a single validated technology platform. Following verification of analytical sensitivity, accuracy, and precision in model and surgical specimens, 152 molecular positive results were generated in lesions representing multiple stages of progression and epithelial differentiation as well as rare subtypes of primary, secondary, or recurring tumors. Single mutations were found in 58% of primary malignant lesions and 12% of benign (P < .001). In the blinded validation set, mutation distribution and frequency were distinct across variants of follicular and papillary carcinomas. BRAF or RET-PTC was detected exclusively in malignant lesions but not in follicular carcinomas (P < .001). RAS or PAX8-PPARG were present in 23% of adenomas, and NRAS was found in a single nonneoplastic lesion (P = .0014). These data substantiate the diagnostic utility of molecular testing for oncogenic mutations and validate its performance in a variety of surgical specimens. Standardized and validated multianalyte molecular panels can complement the preoperative and postoperative assessment of thyroid nodules and support a growing number of clinical and translational applications with potential diagnostic, prognostic, or theranostic utility.

Related: Thyroid Cancer

Simbolo M, Mian C, Barollo S, et al.
High-throughput mutation profiling improves diagnostic stratification of sporadic medullary thyroid carcinomas.
Virchows Arch. 2014; 465(1):73-8 [PubMed] Related Publications
Sporadic medullary thyroid carcinoma (MTC) harbors RET gene somatic mutations in up to 50 % of cases, and RAS family gene mutations occur in about 10 %. A timely and comprehensive characterization of molecular alterations is needed to improve MTC diagnostic stratification and design-tailored therapeutic approaches. Twenty surgically resected sporadic MTCs, previously analyzed for RET mutations by Sanger sequencing using DNA from formalin-fixed paraffin-embedded samples, were investigated for intragenic mutations in 50 cancer-associated genes applying a multigene Ion AmpliSeq next-generation sequencing (NGS) technology. Thirteen (65 %) MTCs harbored a RET mutation; 10 were detected at both Sanger and NGS sequencing, while 3 undetected by Sanger were revealed by NGS. One of the 13 RET-mutated cases also showed an F354L germline mutation in STK11. Of the seven RET wild-type MTCs, four cases (57.1 %) harbored a RAS mutation: three in HRAS (all Q61R) and one in KRAS (G12R). The three remaining MTCs (15 %) resulted as wild-type for all the 50 cancer-related genes. Follow-up was available in all but one RET-mutated case. At the end of follow-up, 7 of 12 (58 %) RET-mutated patients had relapsed, while the 4 RAS-mutated MTC patients were disease-free. Two of the three patients with MTC wild-type for all 50 genes relapsed during the follow-up period. Detection of mutations by NGS has the potential to improve the diagnostic stratification of sporadic MTC.

Related: RET Thyroid Cancer

Liu CX, Li XY, Li CF, et al.
Compound HRAS/PIK3CA mutations in Chinese patients with alveolar rhabdomyosarcomas.
Asian Pac J Cancer Prev. 2014; 15(4):1771-4 [PubMed] Related Publications
The rhabdomyosarcoma (RMS) is the most common type of soft tissue tumor in children and adolescents; yet only a few screens for oncogenic mutations have been conducted for RMS. To identify novel mutations and potential therapeutic targets, we conducted a high-throughput Sequenom mass spectrometry-based analysis of 238 known mutations in 19 oncogenes in 17 primary formalin-fixed paraffin-embedded RMS tissue samples and two RMS cell lines. Mutations were detected in 31.6% (6 of 19) of the RMS specimens. Specifically, mutations in the NRAS gene were found in 27.3% (3 of 11) of embryonal RMS cases, while mutations in NRAS, HRAS, and PIK3CA genes were identified in 37.5% (3 of 8) of alveolar RMS (ARMS) cases; moreover, PIK3CA mutations were found in 25% (2 of 8) of ARMS specimens. The results demonstrate that tumor profiling in archival tissue samples is a useful tool for identifying diagnostic markers and potential therapeutic targets and suggests that these HRAS/ PIK3CA mutations play a critical role in the genesis of RMS.

Grabocka E, Pylayeva-Gupta Y, Jones MJ, et al.
Wild-type H- and N-Ras promote mutant K-Ras-driven tumorigenesis by modulating the DNA damage response.
Cancer Cell. 2014; 25(2):243-56 [PubMed] Article available free on PMC after 10/02/2015 Related Publications
Mutations in KRAS are prevalent in human cancers and universally predictive of resistance to anticancer therapeutics. Although it is widely accepted that acquisition of an activating mutation endows RAS genes with functional autonomy, recent studies suggest that the wild-type forms of Ras may contribute to mutant Ras-driven tumorigenesis. Here, we show that downregulation of wild-type H-Ras or N-Ras in mutant K-Ras cancer cells leads to hyperactivation of the Erk/p90RSK and PI3K/Akt pathways and, consequently, the phosphorylation of Chk1 at an inhibitory site, Ser 280. The resulting inhibition of ATR/Chk1 signaling abrogates the activation of the G2 DNA damage checkpoint and confers specific sensitization of mutant K-Ras cancer cells to DNA damage chemotherapeutic agents in vitro and in vivo.

Related: Cancer Prevention and Risk Reduction AKT1 KRAS gene NRAS

Cullis J, Meiri D, Sandi MJ, et al.
The RhoGEF GEF-H1 is required for oncogenic RAS signaling via KSR-1.
Cancer Cell. 2014; 25(2):181-95 [PubMed] Related Publications
Cellular transformation by oncogenic RAS engages the MAPK pathway under strict regulation by the scaffold protein KSR-1. Here, we report that the guanine nucleotide exchange factor GEF-H1 plays a critical role in a positive feedback loop for the RAS/MAPK pathway independent of its RhoGEF activity. GEF-H1 acts as an adaptor protein linking the PP2A B' subunits to KSR-1, thereby mediating the dephosphorylation of KSR-1 S392 and activation of MAPK signaling. GEF-H1 is important for the growth and survival of HRAS(V12)-transformed cells and pancreatic tumor xenografts. GEF-H1 expression is induced by oncogenic RAS and is correlated with pancreatic neoplastic progression. Our results, therefore, identify GEF-H1 as an amplifier of MAPK signaling and provide mechanistic insight into the progression of RAS mutant tumors.

Related: Cancer of the Pancreas Pancreatic Cancer Signal Transduction

Pinto-Leite R, Carreira I, Melo J, et al.
Genomic characterization of three urinary bladder cancer cell lines: understanding genomic types of urinary bladder cancer.
Tumour Biol. 2014; 35(5):4599-617 [PubMed] Related Publications
Several genomic regions are frequently altered and associated with the type, stage and progression of urinary bladder cancer (UBC). We present the characterization of 5637, T24 and HT1376 UBC cell lines by karyotyping, fluorescence in situ hybridization (FISH), array comparative genomic hybridization (aCGH) and multiplex ligation-dependent probe amplification (MLPA) analysis. Some cytogenetic anomalies present in UBC were found in the three cell lines, such as chromosome 20 aneuploidy and the loss of 9p21. Some gene loci losses (e.g. CDKN2A) and gains (e.g. HRAS, BCL2L1 and PTPN1) were coincident across all cell lines. Although some significant heterogeneity and complexity were detected between them, their genomic profiles exhibited a similar pattern to UBC. We suggest that 5637 and HT1376 represent the E2F3/RB1 pathway due to amplification of 6p22.3, concomitant with loss of one copy of RB1 and mutation of the remaining copy. The HT1376 presented a 10q deletion involving PTEN region and no alteration of PIK3CA region which, in combination with the inactivation of TP53, bears more invasive and metastatic properties than 5637. The T24 belongs to the alternative pathway of FGFR3/CCND1 by presenting mutated HRAS and over-represented CCND1. These cell lines cover the more frequent subtypes of UBC and are reliable models that can be used, as a group, in preclinical studies.

Related: Apoptosis CGH FISH Bladder Cancer Bladder Cancer - Molecular Biology

Richetta AG, Silvestri V, Giancristoforo S, et al.
Mutational profiling in melanocytic tumors: multiple somatic mutations and clinical implications.
Oncology. 2014; 86(2):104-8 [PubMed] Related Publications
In this study, we analyzed multiple somatic mutations in 10 genes relevant in melanoma tumorigenesis and targeted therapies. Overall, 45% of the tumors showed mutations and, in particular, 33% had multiple mutations. Based on our results, we conclude that the assessment of mutation status of multiple genes, including CDKN2A, could provide a genetic profile that can be useful as a prognostic and therapeutic marker in melanocytic tumors.

Related: CDKN2A Melanoma Skin Cancer NRAS

Ceccarelli V, Nocentini G, Billi M, et al.
Eicosapentaenoic acid activates RAS/ERK/C/EBPβ pathway through H-Ras intron 1 CpG island demethylation in U937 leukemia cells.
PLoS One. 2014; 9(1):e85025 [PubMed] Article available free on PMC after 10/02/2015 Related Publications
Epigenetic alterations, including aberrant DNA methylation, contribute to tumor development and progression. Silencing of tumor suppressor genes may be ascribed to promoter DNA hypermethylation, a reversible phenomenon intensely investigated as potential therapeutic target. Previously, we demonstrated that eicosapentaenoic acid (EPA) exhibits a DNA demethylating action that promotes the re-expression of the tumor suppressor gene CCAAT/enhancer-binding protein δ (C/EBPδ). The C/EBPβ/C/EBPδ heterodimer formed appears essential for the monocyte differentiation commitment. The present study aims to evaluate the effect of EPA on RAS/extracellular signal regulated kinases (ERK1/2)/C/EBPβ pathway, known to be induced during the monocyte differentiation program. We found that EPA conditioning of U937 leukemia cells activated RAS/ERK/C/EBPβ pathway, increasing the C/EBPβ and ERK1/2 active phosphorylated forms. Transcriptional induction of the upstream activator H-Ras gene resulted in increased expression of H-Ras protein in the active pool of non raft membrane fraction. H-Ras gene analysis identified an hypermethylated CpG island in intron 1 that can affect the DNA-protein interaction modifying RNA polymerase II (RNAPII) activity. EPA treatment demethylated almost completely this CpG island, which was associated with an enrichment of active RNAPII. The increased binding of the H-Ras transcriptional regulator p53 to its consensus sequence within the intronic CpG island further confirmed the effect of EPA as demethylating agent. Our results provide the first evidence that an endogenous polyunsaturated fatty acid (PUFA) promotes a DNA demethylation process responsible for the activation of RAS/ERK/C/EBPβ pathway during the monocyte differentiation commitment. The new role of EPA as demethylating agent paves the way for studying PUFA action when aberrant DNA methylation is involved.

Related: Azacitidine Leukemia TP53

Shern JF, Chen L, Chmielecki J, et al.
Comprehensive genomic analysis of rhabdomyosarcoma reveals a landscape of alterations affecting a common genetic axis in fusion-positive and fusion-negative tumors.
Cancer Discov. 2014; 4(2):216-31 [PubMed] Related Publications
UNLABELLED: Despite gains in survival, outcomes for patients with metastatic or recurrent rhabdomyosarcoma remain dismal. In a collaboration between the National Cancer Institute, Children's Oncology Group, and Broad Institute, we performed whole-genome, whole-exome, and transcriptome sequencing to characterize the landscape of somatic alterations in 147 tumor/normal pairs. Two genotypes are evident in rhabdomyosarcoma tumors: those characterized by the PAX3 or PAX7 fusion and those that lack these fusions but harbor mutations in key signaling pathways. The overall burden of somatic mutations in rhabdomyosarcoma is relatively low, especially in tumors that harbor a PAX3/7 gene fusion. In addition to previously reported mutations in NRAS, KRAS, HRAS, FGFR4, PIK3CA, and CTNNB1, we found novel recurrent mutations in FBXW7 and BCOR, providing potential new avenues for therapeutic intervention. Furthermore, alteration of the receptor tyrosine kinase/RAS/PIK3CA axis affects 93% of cases, providing a framework for genomics-directed therapies that might improve outcomes for patients with rhabdomyosarcoma.
SIGNIFICANCE: This is the most comprehensive genomic analysis of rhabdomyosarcoma to date. Despite a relatively low mutation rate, multiple genes were recurrently altered, including NRAS, KRAS, HRAS, FGFR4, PIK3CA, CTNNB1, FBXW7, and BCOR. In addition, a majority of rhabdomyosarcoma tumors alter the receptor tyrosine kinase/RAS/PIK3CA axis, providing an opportunity for genomics-guided intervention.

Related: Rhabdomyosarcoma Signal Transduction

Nutter F, Holen I, Brown HK, et al.
Different molecular profiles are associated with breast cancer cell homing compared with colonisation of bone: evidence using a novel bone-seeking cell line.
Endocr Relat Cancer. 2014; 21(2):327-41 [PubMed] Related Publications
Advanced breast cancer is associated with the development of incurable bone metastasis. The two key processes involved, tumour cell homing to and subsequent colonisation of bone, remain to be clearly defined. Genetic studies have indicated that different genes facilitate homing and colonisation of secondary sites. To identify specific changes in gene and protein expression associated with bone-homing or colonisation, we have developed a novel bone-seeking clone of MDA-MB-231 breast cancer cells that exclusively forms tumours in long bones following i.v. injection in nude mice. Bone-homing cells were indistinguishable from parental cells in terms of growth rate in vitro and when grown subcutaneously in vivo. Only bone-homing ability differed between the lines; once established in bone, tumours from both lines displayed similar rates of progression and caused the same extent of lytic bone disease. By comparing the molecular profile of a panel of metastasis-associated genes, we have identified differential expression profiles associated with bone-homing or colonisation. Bone-homing cells had decreased expression of the cell adhesion molecule fibronectin and the migration and calcium signal binding protein S100A4, in addition to increased expression of interleukin 1B. Bone colonisation was associated with increased fibronectin and upregulation of molecules influencing signal transduction pathways and breakdown of extracellular matrix, including hRAS and matrix metalloproteinase 9. Our data support the hypothesis that during early stages of breast cancer bone metastasis, a specific set of genes are altered to facilitate bone-homing, and that disruption of these may be required for effective therapeutic targeting of this process.

Related: Breast Cancer

Chiosea SI, Grandis JR, Lui VW, et al.
PIK3CA, HRAS and PTEN in human papillomavirus positive oropharyngeal squamous cell carcinoma.
BMC Cancer. 2013; 13:602 [PubMed] Article available free on PMC after 10/02/2015 Related Publications
BACKGROUND: Recent genomic evidence suggests frequent phosphatidylinositide 3-kinase (PI3K) pathway activation in human papillomavirus (HPV) positive oropharyngeal squamous cell carcinoma. Mutations/amplification of the gene encoding p110α catalytic subunit of phosphoinositide 3-kinase (PIK3CA), loss of phosphatase and tensin homolog (PTEN) and HRAS mutations are known to activate PI3K pathway.
METHODS AND RESULTS: PIK3CA mutations were identified by Sanger sequencing in 23 of 75 (31%) HPV-positive oropharyngeal carcinomas, including exon 9 (p.E545K [n = 10] and p.E542K [n = 5]) or exon 20 (p.H1047Y, n = 2) mutations. Five rare and one novel (p.R537Q) PIK3CA mutations were identified. HRAS mutation (p.Q61L) was detected in 1 of 62 tested cases. PIK3CA amplification by fluorescence in situ hybridization (FISH) was identified in 4 cases (4/21, 20%), while PTEN loss was seen in 7 (7/21, 33%) cases (chromosome 10 monosomy [n = 4], homozygous deletion [n = 3]).
CONCLUSIONS: Overall, genetic alterations that likely lead to PI3K pathway activation were identified in 34 of 75 cases (45%) and did not correlate with disease specific survival. These findings offer a molecular rationale for therapeutic targeting of PI3K pathway in patients with HPV-positive oropharyngeal carcinoma.

Related: Oropharyngeal Cancer PTEN

Deng BY, Hua YQ, Cai ZD
Establishing an osteosarcoma associated protein-protein interaction network to explore the pathogenesis of osteosarcoma.
Eur J Med Res. 2013; 18:57 [PubMed] Article available free on PMC after 10/02/2015 Related Publications
BACKGROUND: The aim of this study was to establish an osteosarcoma (OS) associated protein-protein interaction network and explore the pathogenesis of osteosarcoma.
METHODS: The gene expression profile GSE9508 was downloaded from the Gene Expression Omnibus database, including five samples of non-malignant bone (the control), seven samples for non-metastatic patients (six of which were analyzed in duplicate), and 11 samples for metastatic patients (10 of which were analyzed in duplicate). Differentially expressed genes (DEGs) between osteosarcoma and control samples were identified by packages in R with the threshold of |logFC (fold change)| > 1 and false discovery rate < 0.05. Osprey software was used to construct the interaction network of DEGs, and genes at protein-protein interaction (PPI) nodes with high degrees were identified. The Database for Annotation, Visualization and Integrated Discovery and WebGestalt software were then used to perform functional annotation and pathway enrichment analyses for PPI networks, in which P < 0.05 was considered statistically significant.
RESULTS: Compared to the control samples, the expressions of 42 and 341 genes were altered in non-metastatic OS and metastatic OS samples, respectively. A total of 15 significantly enriched functions were obtained with Gene Ontology analysis (P < 0.05). The DEGs were classified and significantly enriched in three pathways, including the tricarboxylic acid cycle, lysosome and axon guidance. Genes such as HRAS, IDH3A, ATP6ap1, ATP6V0D2, SEMA3F and SEMA3A were involved in the enriched pathways.
CONCLUSIONS: The hub genes from metastatic OS samples are not only bio-markers of OS, but also help to improve therapies for OS.

Related: Osteosarcoma Signal Transduction

Mutational landscape of gingivo-buccal oral squamous cell carcinoma reveals new recurrently-mutated genes and molecular subgroups.
Nat Commun. 2013; 4:2873 [PubMed] Article available free on PMC after 10/02/2015 Related Publications
Gingivo-buccal oral squamous cell carcinoma (OSCC-GB), an anatomical and clinical subtype of head and neck squamous cell carcinoma (HNSCC), is prevalent in regions where tobacco-chewing is common. Exome sequencing (n=50) and recurrence testing (n=60) reveals that some significantly and frequently altered genes are specific to OSCC-GB (USP9X, MLL4, ARID2, UNC13C and TRPM3), while some others are shared with HNSCC (for example, TP53, FAT1, CASP8, HRAS and NOTCH1). We also find new genes with recurrent amplifications (for example, DROSHA, YAP1) or homozygous deletions (for example, DDX3X) in OSCC-GB. We find a high proportion of C>G transversions among tobacco users with high numbers of mutations. Many pathways that are enriched for genomic alterations are specific to OSCC-GB. Our work reveals molecular subtypes with distinctive mutational profiles such as patients predominantly harbouring mutations in CASP8 with or without mutations in FAT1. Mean duration of disease-free survival is significantly elevated in some molecular subgroups. These findings open new avenues for biological characterization and exploration of therapies.

Related: Oral Cancer TP53 FAT1

Giannoulatou E, McVean G, Taylor IB, et al.
Contributions of intrinsic mutation rate and selfish selection to levels of de novo HRAS mutations in the paternal germline.
Proc Natl Acad Sci U S A. 2013; 110(50):20152-7 [PubMed] Article available free on PMC after 10/02/2015 Related Publications
The RAS proto-oncogene Harvey rat sarcoma viral oncogene homolog (HRAS) encodes a small GTPase that transduces signals from cell surface receptors to intracellular effectors to control cellular behavior. Although somatic HRAS mutations have been described in many cancers, germline mutations cause Costello syndrome (CS), a congenital disorder associated with predisposition to malignancy. Based on the epidemiology of CS and the occurrence of HRAS mutations in spermatocytic seminoma, we proposed that activating HRAS mutations become enriched in sperm through a process akin to tumorigenesis, termed selfish spermatogonial selection. To test this hypothesis, we quantified the levels, in blood and sperm samples, of HRAS mutations at the p.G12 codon and compared the results to changes at the p.A11 codon, at which activating mutations do not occur. The data strongly support the role of selection in determining HRAS mutation levels in sperm, and hence the occurrence of CS, but we also found differences from the mutation pattern in tumorigenesis. First, the relative prevalence of mutations in sperm correlates weakly with their in vitro activating properties and occurrence in cancers. Second, specific tandem base substitutions (predominantly GC>TT/AA) occur in sperm but not in cancers; genomewide analysis showed that this same mutation is also overrepresented in constitutional pathogenic and polymorphic variants, suggesting a heightened vulnerability to these mutations in the germline. We developed a statistical model to show how both intrinsic mutation rate and selfish selection contribute to the mutational burden borne by the paternal germline.

Avitan-Hersh E, Tatur S, Indelman M, et al.
Postzygotic HRAS mutation causing both keratinocytic epidermal nevus and thymoma and associated with bone dysplasia and hypophosphatemia due to elevated FGF23.
J Clin Endocrinol Metab. 2014; 99(1):E132-6 [PubMed] Related Publications
INTRODUCTION: Epidermal nevus syndrome is a rare group of disorders characterized by the combination of congenital epidermal nevi and extracutaneous features, including skeletal, neurological, ocular, and other systemic findings. We report a case of keratinocytic epidermal nevus syndrome that includes a thymoma, bone dysplasia, and hypophosphatemia with elevated fibroblast growth factor 23 (FGF23) levels associated with postzygotic HRAS mutation.
CASE REPORT: A 14-year-old boy was admitted due to recent limping. The physical examination revealed multiple right-sided linear epidermal nevi along Blaschko's lines. Magnetic resonance imaging showed cystic lesions in cervical bones and thymoma, and x-ray examination showed cystic lesions in the hands. Biochemical studies demonstrated severe hypophosphatemia, normocalcemia, high normal PTH, low 25-hydroxyvitamin D and low 1,25-dihydroxyvitamin D levels. The serum FGF23 C-terminal level was normal, but the intact FGF23 level was found to be elevated. Genetic evaluation revealed a heterozygote mutation in the HRAS gene in both the keratinocytic epidermal nevus and thymoma but not in DNA extracted from blood lymphocytes, thus establishing the mutation as postzygotic.
DISCUSSION: Postzygotic mutations in HRAS lead to elevation of FGF23 levels, as found in mutated PHEX, FGF23, DMP1, and ENPP1 genes, which lead to hypophosphatemia.
CONCLUSION: An identical postzygotic HRAS mutation was shown to be present in both keratinocytic epidermal nevus and thymoma and to be associated with bone lesions and hypophosphatemia due to elevated FGF23 levels. These may all be related to the HRAS mutation.

Related: Skin Cancer Thymoma and Thymic Carcinoma

Zanaruddin SN, Yee PS, Hor SY, et al.
Common oncogenic mutations are infrequent in oral squamous cell carcinoma of Asian origin.
PLoS One. 2013; 8(11):e80229 [PubMed] Article available free on PMC after 10/02/2015 Related Publications
OBJECTIVES: The frequency of common oncogenic mutations and TP53 was determined in Asian oral squamous cell carcinoma (OSCC).
MATERIALS AND METHODS: The OncoCarta(™) panel v1.0 assay was used to characterize oncogenic mutations. In addition, exons 4-11 of the TP53 gene were sequenced. Statistical analyses were conducted to identify associations between mutations and selected clinico-pathological characteristics and risk habits.
RESULTS: Oncogenic mutations were detected in PIK3CA (5.7%) and HRAS (2.4%). Mutations in TP53 were observed in 27.7% (31/112) of the OSCC specimens. Oncogenic mutations were found more frequently in non-smokers (p = 0.049) and TP53 truncating mutations were more common in patients with no risk habits (p = 0.019). Patients with mutations had worse overall survival compared to those with absence of mutations; and patients who harbored DNA binding domain (DBD) and L2/L3/LSH mutations showed a worse survival probability compared to those patients with wild type TP53. The majority of the oncogenic and TP53 mutations were G:C > A:T and A:T > G:C base transitions, regardless of the different risk habits.
CONCLUSION: Hotspot oncogenic mutations which are frequently present in common solid tumors are exceedingly rare in OSCC. Despite differences in risk habit exposure, the mutation frequency of PIK3CA and HRAS in Asian OSCC were similar to that reported in OSCC among Caucasians, whereas TP53 mutations rates were significantly lower. The lack of actionable hotspot mutations argue strongly for the need to comprehensively characterize gene mutations associated with OSCC for the development of new diagnostic and therapeutic tools.

Related: Oral Cancer TP53

Schulten HJ, Salama S, Al-Ahmadi A, et al.
Comprehensive survey of HRAS, KRAS, and NRAS mutations in proliferative thyroid lesions from an ethnically diverse population.
Anticancer Res. 2013; 33(11):4779-84 [PubMed] Related Publications
BACKGROUND: The distribution and kind of rat sarcoma viral oncogenes homolog (RAS) mutations, as well as their clinical impact on different types of thyroid lesions, vary widely among the different populations studied. We performed a comprehensive mutational survey in the highly related RAS genes HRAS, KRAS, and NRAS in a case series of proliferative thyroid lesions with known BRAF mutational status, originating from an ethnically diverse group.
MATERIALS AND METHODS: Mutational hotspot regions encompassing codons 12, 13, and 61 of the RAS genes were directly sequenced in 381 cases of thyroid lesions. In addition, the putative NRAS hotspot region encompassing codon 97 was sequenced in 36 thyroid lesions. The case series included lesions of Hashimoto's thyroiditis (HT), nodular goiters, hyperplastic nodules, follicular adenomas (FAs), Hurthle cell variants of FA, papillary thyroid carcinomas (PTCs), follicular variants of PTC (FVPTCs), microcarcinomas of PTC (micro PTCs; tumor size ≤1 cm), follicular TCs (FTCs), Hurthle cell variants of FTC, and non-well-differentiated TCs (NWDTCs).
RESULTS: We identified RAS mutations in 16 out of 57 (28.1%) FAs, 2 out of 8 (25%) NWDTCs, 8 out of 42 (19.0%) FVPTCs, 2 out of 10 (20.0%) FTCs, 1 out of 12 (8.3%) Hurthle cell variants of FA, 3 out of 46 (6.5%) goiters, 1 out of 18 (5.6%) hyperplastic nodules, 3 out of 56 (5.4%) micro PTCs, 2 out of 115 (1.7%) PTCs, 0 out of 7 (0%) Hurthle cell variants of FTC, and 0 out of 10 (0%) HT lesions. NRAS codon 61 mutation was the predominant form, followed by HRAS codon 61 mutation. Only three mutations affected RAS codons 12 and 13, two of which were identified in goiters. No codon 97 mutation was detected in the examined FVPTCs. An as yet undescribed deletion of KRAS codon 59 was identified in one FA.
DISCUSSION: RAS mutations in our case series were commonly associated with follicular-patterned thyroid lesions. Our data suggest that FAs with a RAS mutation may constitute precursor lesions for TC with follicular histology. The newly-discovered KRAS codon 59 deletion is one of the first reported codon deletions in a RAS hotspot region.

Related: Thyroid Cancer NRAS

Swiderek E, Kalas W, Wysokinska E, et al.
The interplay between epigenetic silencing, oncogenic KRas and HIF-1 regulatory pathways in control of BNIP3 expression in human colorectal cancer cells.
Biochem Biophys Res Commun. 2013; 441(4):707-12 [PubMed] Related Publications
Bcl-2/adenovirus E1B-19kDa-interacting protein 3 (BNIP3) is an important mediator of cell survival and a member of the Bcl-2 family of proteins that regulate programmed cell death and autophagy. We have previously established a link between the expression of oncogenic HRas and up-regulation of BNIP3 and the control of autophagy in cancer cells. However, in view of varied expression of BNIP3 in different tumor types and emerging uncertainties as to the role of epigenetic silencing, oncogenic regulation and the role of BNIP3 in cancer are still poorly understood. In the present study we describe profound effect of KRas on the expression of methylated BNIP3 in colorectal cancer cells and explore the interplay between HIF-1, hypoxia pathway and oncogenic KRas in this context. We observed that BNIP3 mRNA remains undetectable in aggressive DLD-1 cells harboring G13D mutant KRAS and HT-29 colorectal cancer cells unless the cells are exposed to demethylating agents such as 5-aza-2'-deoxycytidine. Following this treatment BNIP3 expression remains uniquely dependent on the Ras activity. We found that hypoxia or pharmacological activation of HIF-1 alone contributes to, but is not sufficient for efficient induction of BNIP3 mRNA transcription in cells lacking mutant KRas activity. The up-regulation of BNIP3 by KRas in this setting is mediated by the MAPK pathway, and is attenuated by the respective inhibitors (PD98059, U0126). Thus, we demonstrate the novel mechanism where activity of Ras is essential for 5-aza-2'-deoxycytidine-mediated BNIP3 expression. Moreover, we found that 5-aza-2'-deoxycytidine-mediated or enforced up-regulation of BNIP3 in DLD-1 cells results in KRas-dependent resistance to 5-Fluorouracil.

Related: Colorectal (Bowel) Cancer Fluorouracil KRAS gene

Calderaro J, Rebouissou S, de Koning L, et al.
PI3K/AKT pathway activation in bladder carcinogenesis.
Int J Cancer. 2014; 134(8):1776-84 [PubMed] Related Publications
The PI3K/AKT pathway is considered to play a major role in bladder carcinogenesis, but its relationships with other molecular alterations observed in bladder cancer remain unknown. We investigated PI3K/AKT pathway activation in a series of human bladder urothelial carcinomas (UC) according to PTEN expression, PTEN deletions and FGFR3, PIK3CA, KRAS, HRAS, NRAS and TP53 gene mutations. The series included 6 normal bladder urothelial samples and 129 UC (Ta n = 25, T1 n = 34, T2-T3-T4 n = 70). Expression of phospho-AKT (pAKT), phospho-S6-Ribosomal Protein (pS6) (one downstream effector of PI3K/AKT pathway) and PTEN was evaluated by reverse phase protein Array. Expression of miR-21, miR-19a and miR-222, known to regulate PTEN expression, was also evaluated. pAKT expression levels were higher in tumors than in normal urothelium (p < 0.01), regardless of stage and showed a weak and positive correlation with pS6 (Spearman coefficient RS = 0.26; p = 0.002). No association was observed between pAKT or pS6 expression and the gene mutations studied. PTEN expression was decreased in PTEN-deleted tumors, and in T1 (p = 0.0089) and T2-T3-T4 (p < 0.001) tumors compared to Ta tumors; it was also negatively correlated with miR-19a (RS = -0.50; p = 0.0088) and miR-222 (RS = -0.48; p = 0.0132), but not miR-21 (RS = -0.27; p = 0.18) expression. pAKT and PTEN expressions were not negatively correlated, and, on the opposite, a positive and moderate correlation was observed in Ta (RS = 0.54; p = 0.0056) and T1 (RS = 0.56; p = 0.0006) tumors. Our study suggests that PI3K/AKT pathway activation occurs in the entire spectrum of bladder UC regardless of stage or known most frequent molecular alterations, and independently of low PTEN expression.

Related: PTEN AKT1 Signal Transduction TP53 Bladder Cancer Bladder Cancer - Molecular Biology KRAS gene miR-21 NRAS

Basile KJ, Abel EV, Dadpey N, et al.
In vivo MAPK reporting reveals the heterogeneity in tumoral selection of resistance to RAF inhibitors.
Cancer Res. 2013; 73(23):7101-10 [PubMed] Article available free on PMC after 10/02/2015 Related Publications
Activation of the ERK1/2 mitogen-activated protein kinases (MAPK) confers resistance to the RAF inhibitors vemurafenib and dabrafenib in mutant BRAF-driven melanomas. Methods to understand how resistance develops are important to optimize the clinical use of RAF inhibitors in patients. Here, we report the development of a novel ERK1/2 reporter system that provides a noninvasive, quantitative, and temporal analysis of RAF inhibitor efficacy in vivo. Use of this system revealed heterogeneity in the level of ERK1/2 reactivation associated with acquired resistance to RAF inhibition. We identified several distinct novel and known molecular changes in resistant tumors emerging from treatment-naïve cell populations including BRAF V600E variants and HRAS mutation, both of which were required and sufficient for ERK1/2 reactivation and drug resistance. Our work offers an advance in understanding RAF inhibitor resistance and the heterogeneity in resistance mechanisms, which emerge from a malignant cell population.

Related: Cancer Prevention and Risk Reduction BRAF gene

Liu Y, Liu CX, Wu ZT, et al.
Mining proteins associated with oral squamous cell carcinoma in complex networks.
Asian Pac J Cancer Prev. 2013; 14(8):4621-5 [PubMed] Related Publications
The purpose of this study was to construct a protein-protein interaction (PPI) network related to oral squamous cell carcinoma (OSCC). Each protein was ranked and those most associated with OSCC were mined within the network. First, OSCC-related genes were retrieved from the Online Mendelian Inheritance in Man (OMIM) database. Then they were mapped to their protein identifiers and a seed set of proteins was built. The seed proteins were expanded using the nearest neighbor expansion method to construct a PPI network through the Online Predicated Human Interaction Database (OPHID). The network was verified to be statistically significant, the score of each protein was evaluated by algorithm, then the OSCC-related proteins were ranked. 38 OSCC related seed proteins were expanded to 750 protein pairs. A protein-protein interaction nerwork was then constructed and the 30 top-ranked proteins listed. The four highest-scoring seed proteins were SMAD4, CTNNB1, HRAS, NOTCH1, and four non-seed proteins P53, EP300, SMAD3, SRC were mined using the nearest neighbor expansion method. The methods shown here may facilitate the discovery of important OSCC proteins and guide medical researchers in further pertinent studies.

Related: Oral Cancer

Lim YH, Ovejero D, Sugarman JS, et al.
Multilineage somatic activating mutations in HRAS and NRAS cause mosaic cutaneous and skeletal lesions, elevated FGF23 and hypophosphatemia.
Hum Mol Genet. 2014; 23(2):397-407 [PubMed] Article available free on PMC after 15/01/2015 Related Publications
Pathologically elevated serum levels of fibroblast growth factor-23 (FGF23), a bone-derived hormone that regulates phosphorus homeostasis, result in renal phosphate wasting and lead to rickets or osteomalacia. Rarely, elevated serum FGF23 levels are found in association with mosaic cutaneous disorders that affect large proportions of the skin and appear in patterns corresponding to the migration of ectodermal progenitors. The cause and source of elevated serum FGF23 is unknown. In those conditions, such as epidermal and large congenital melanocytic nevi, skin lesions are variably associated with other abnormalities in the eye, brain and vasculature. The wide distribution of involved tissues and the appearance of multiple segmental skin and bone lesions suggest that these conditions result from early embryonic somatic mutations. We report five such cases with elevated serum FGF23 and bone lesions, four with large epidermal nevi and one with a giant congenital melanocytic nevus. Exome sequencing of blood and affected skin tissue identified somatic activating mutations of HRAS or NRAS in each case without recurrent secondary mutation, and we further found that the same mutation is present in dysplastic bone. Our finding of somatic activating RAS mutation in bone, the endogenous source of FGF23, provides the first evidence that elevated serum FGF23 levels, hypophosphatemia and osteomalacia are associated with pathologic Ras activation and may provide insight in the heretofore limited understanding of the regulation of FGF23.

Related: Skin Cancer NRAS

Beronja S, Janki P, Heller E, et al.
RNAi screens in mice identify physiological regulators of oncogenic growth.
Nature. 2013; 501(7466):185-90 [PubMed] Article available free on PMC after 15/01/2015 Related Publications
Tissue growth is the multifaceted outcome of a cell's intrinsic capabilities and its interactions with the surrounding environment. Decoding these complexities is essential for understanding human development and tumorigenesis. Here we tackle this problem by carrying out the first genome-wide RNA-interference-mediated screens in mice. Focusing on skin development and oncogenic (Hras(G12V)-induced) hyperplasia, our screens uncover previously unknown as well as anticipated regulators of embryonic epidermal growth. Among the top oncogenic screen hits are Mllt6 and the Wnt effector β-catenin, which maintain Hras(G12V)-dependent hyperproliferation. We also expose β-catenin as an unanticipated antagonist of normal epidermal growth, functioning through Wnt-independent intercellular adhesion. Finally, we validate functional significance in mouse and human cancers, thereby establishing the feasibility of in vivo mammalian genome-wide investigations to dissect tissue development and tumorigenesis. By documenting some oncogenic growth regulators, we pave the way for future investigations of other hits and raise promise for unearthing new targets for cancer therapies.

Related: Cancer Prevention and Risk Reduction Signal Transduction Skin Cancer CTNNB1 gene

Cros J, Sbidian E, Hans S, et al.
Expression and mutational status of treatment-relevant targets and key oncogenes in 123 malignant salivary gland tumours.
Ann Oncol. 2013; 24(10):2624-9 [PubMed] Related Publications
BACKGROUND: Malignant tumours of the salivary glands (MSGT) are rare and pleomorphic entities. Patients with advanced disease may benefit from targeted therapy; however, specific targets for optimising and personalising treatments are yet to be identified.
DESIGN: Immunohistochemistry for C-KIT, EGFR, HER2, MUC1, phospho-mTOR, androgen/estrogens/progesterone receptors and Ki67 was carried out and evaluated in terms of progression-free and overall survival. High throughput molecular screening of key oncogenes was done in 107 patients using routine diagnostic methods and Sequenom technology.
RESULTS: Several therapy leads were identified, including high levels of HER2 and androgen receptors in salivary duct carcinomas, C-KIT in myoepithelial carcinomas and EGFR in mucoepidermoid carcinomas. Recurrent mutations involving downstream elements of the EGFR pathway were found in HRAS, notably in tumours with a myoepithelial component, and in other key oncogenes (KRAS/NRAS/PI3KCA/BRAF/MAP2K). On the other hand, <1% of samples had EGFR or HER2 mutations.
CONCLUSION: Several tumour subtypes overexpressed targets of directed therapies suggesting potential therapy leads. Genotyping results suggest activation downstream of EGFR in 18 of the 107 samples that could be associated with low efficacy of EGFR inhibitors. Other molecules, such as PI3K/MEK or mTOR inhibitors, may have anti-tumour activity in this subgroup. The high mutation rate in HRAS highlights a novel key oncogenic event in MSGT.

Related: Salivary Gland Cancer EGFR

Elangovan S, Pathania R, Ramachandran S, et al.
Molecular mechanism of SLC5A8 inactivation in breast cancer.
Mol Cell Biol. 2013; 33(19):3920-35 [PubMed] Article available free on PMC after 15/01/2015 Related Publications
SLC5A8 is a putative tumor suppressor that is inactivated in more than 10 different types of cancer, but neither the oncogenic signaling responsible for SLC5A8 inactivation nor the functional relevance of SLC5A8 loss to tumor growth has been elucidated. Here, we identify oncogenic HRAS (HRAS(G12V)) as a potent mediator of SLC5A8 silencing in human nontransformed normal mammary epithelial cell lines and in mouse mammary tumors through DNMT1. Further, we demonstrate that loss of Slc5a8 increases cancer-initiating stem cell formation and promotes mammary tumorigenesis and lung metastasis in an HRAS-driven murine model of mammary tumors. Mammary-gland-specific overexpression of Slc5a8 (mouse mammary tumor virus-Slc5a8 transgenic mice), as well as induction of endogenous Slc5a8 in mice with inhibitors of DNA methylation, protects against HRAS-driven mammary tumors. Collectively, our results provide the tumor-suppressive role of SLC5A8 and identify the oncogenic HRAS as a mediator of tumor-associated silencing of this tumor suppressor in mammary glands. These findings suggest that pharmacological approaches to reactivate SLC5A8 expression in tumor cells have potential as a novel therapeutic strategy for breast cancer treatment.

Related: Breast Cancer SLC5A8

Eszlinger M, Krogdahl A, Münz S, et al.
Impact of molecular screening for point mutations and rearrangements in routine air-dried fine-needle aspiration samples of thyroid nodules.
Thyroid. 2014; 24(2):305-13 [PubMed] Related Publications
BACKGROUND: The diagnostic limitations of thyroid fine-needle aspiration (FNA), such as the indeterminate category, can be partially overcome by molecular analyses. However, until now, rearrangements have only been detected in fresh FNA material and the number of follicular thyroid carcinomas (FTCs) was rather low in previous studies. We aimed at investigating the impact of point mutations and rearrangement detection in a set of routine air-dried FNA smears with a higher percentage of FTCs.
METHODS: RNA and DNA was extracted from 310 FNAs (164 indeterminate, 57 malignant, 89 benign) and corresponding formalin-fixed paraffin-embedded tissue (156 follicular adenomas [FAs], 32 FTCs, 44 papillary thyroid carcinomas [PTCs], 9 follicular variant PTCs, and 69 goiters). PAX8/PPARG and RET/PTC rearrangements were detected by qPCR, BRAF and RAS mutations by high-resolution melting PCR and by pyrosequencing.
RESULTS: Forty-seven mutations were detected in the FNAs: 22 BRAF, 13 NRAS, and 3 HRAS mutations, 8 PAX8/PPARG, and one RET/PTC-rearrangement. While the presence of a BRAF and RET/PTC mutation was associated with cancer in 100% of samples each, the presence of a RAS and PAX8/PPARG mutation was associated with cancer in only 12% and 50% of samples, respectively. In the indeterminate group 4 of 25 carcinomas were identified by molecular FNA screening, which increased the sensitivity from 67% (cytology alone) to 75% (cytology plus molecular screening).
CONCLUSION: Molecular screening for point mutations and rearrangements is feasible in air-dried FNAs. Although the impact of detecting point mutations and rearrangements in FNAs has most likely been overestimated in previous studies, molecular FNA analyses improve presurgical diagnostics. The detection of BRAF mutations in FNA may improve the choice of surgery and postsurgical treatment. Further data are necessary to elucidate the true impact of detecting RAS and PAX8/PPARG mutations in FNAs. The inclusion of additional rare somatic mutations and miRNA markers might further improve the impact of molecular FNA diagnostics.

Related: PPARG gene BRAF gene RET PAX8 gene


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Cite this page: Cotterill SJ. HRAS, Cancer Genetics Web: http://www.cancerindex.org/geneweb/HRAS.htm Accessed: date

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