PTCH2; patched 2 (1p34.1)

Gene Summary

Gene:PTCH2; patched 2
Aliases: PTC2
Summary:This gene encodes a transmembrane receptor of the patched gene family. The encoded protein may function as a tumor suppressor in the hedgehog signaling pathway. Alterations in this gene have been associated with nevoid basal cell carcinoma syndrome, basal cell carcinoma, medulloblastoma, and susceptibility to congenital macrostomia. Alternatively spliced transcript variants have been described.[provided by RefSeq, Oct 2009]
Databases:OMIM, VEGA, HGNC, Ensembl, GeneCard, Gene
Protein:protein patched homolog 2
Updated:15 January, 2015


What does this gene/protein do?
Show (7)


What pathways are this gene/protein implicaed in?
- Hedgehog signaling pathway KEGG
Data from KEGG and BioCarta [BIOCARTA terms] via CGAP

Cancer Overview

Research Indicators

Publications Per Year (1990-2015)
Graph generated 15 January 2015 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.

Tag cloud generated 15 January, 2015 using data from PubMed, MeSH and CancerIndex

Notable (7)

Scope includes mutations and abnormal protein expression.

Entity Topic PubMed Papers
Skin, Basal Cell CarcinomaPTCH2 and Basal Cell Carcinoma (BCC) - Skin View Publications8
Skin CancerPTCH2 and Skin Cancer View Publications5
Basal Cell Nevus SyndromePTCH2 mutation in Basal Cell Nevus Syndrome View Publications4
Stomach CancerPTCH2 and Stomach Cancer View Publications2
-PTCH2 and Jaw Neoplasms View Publications2
Uterine SarcomaPTCH2 and Uterine Cancer View Publications2
Cervical CancerPTCH2 and Cervical Cancer View Publications1

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: PTCH2 (cancer-related)

Buza N, Xu F, Wu W, et al.
Recurrent chromosomal aberrations in intravenous leiomyomatosis of the uterus: high-resolution array comparative genomic hybridization study.
Hum Pathol. 2014; 45(9):1885-92 [PubMed] Related Publications
Uterine intravenous leiomyomatosis (IVL) is a distinct smooth muscle neoplasm with a potential of clinical aggressiveness due to its ability to extend into intrauterine and extrauterine vasculature. In this study, chromosomal alterations analyzed by oligonucleotide array comparative genomic hybridization were performed in 9 cases of IVL. The analysis was informative in all cases with multiple copy number losses and/or gains observed in each tumor. The most frequent recurrent loss of 22q12.3-q13.1 was observed in 6 tumors (66.7%), followed by losses of 22q11.23-q13.31, 1p36.13-p33, 2p25.3-p23.3, and 2q24.2-q32.2 and gains of 6p22.2, 2q37.3 and 10q22.2-q22.3, in decreasing order of frequency. Copy number variants were identified at 14q11.2, 15q11.1-q11.2, and 15q26.2. Genes mapping to the regions of loss include CHEK2, EWS, NF2, PDGFB, and MAP3K7IP1 on chromosome 22q, HEI10 on chromosome 14q, and succinate dehydrogenase subunit B, E2F2, ARID1A KPNA6, EIF3S2 , PTCH2, and PIK3R3 on chromosome 1p. Regional losses on chromosomes 22q and 1p and gains on chromosomes 12q showed overlaps with those previously observed in uterine leiomyosarcomas. In addition, presence of multiple chromosomal aberrations implies a higher level of genetic instability. Follow-up polymerase chain reaction (PCR) sequencing analysis of MED12 gene revealed absence of G> A transition at nucleotides c.130 or c.131 in all 9 cases, a frequent mutation found in uterine leiomyoma and its variants. In conclusion, this is the first report of high-resolution, genome-wide investigation of IVL by oligonucleotide array comparative genomic hybridization. The presence of high frequencies of recurrent regional loss involving several chromosomes is an important finding and likely related to the pathogenesis of the disease.

Related: CGH

Shimada Y, Katsube K, Kabasawa Y, et al.
Integrated genotypic analysis of hedgehog-related genes identifies subgroups of keratocystic odontogenic tumor with distinct clinicopathological features.
PLoS One. 2013; 8(8):e70995 [PubMed] Free Access to Full Article Related Publications
Keratocystic odontogenic tumor (KCOT) arises as part of Gorlin syndrome (GS) or as a sporadic lesion. Gene mutations and loss of heterozygosity (LOH) of the hedgehog receptor PTCH1 plays an essential role in the pathogenesis of KCOT. However, some KCOT cases lack evidence for gene alteration of PTCH1, suggesting that other genes in the hedgehog pathway may be affected. PTCH2 and SUFU participate in the occurrence of GS-associated tumors, but their roles in KCOT development are unknown. To elucidate the roles of these genes, we enrolled 36 KCOT patients in a study to sequence their entire coding regions of PTCH1, PTCH2 and SUFU. LOH and immunohistochemical expression of these genes, as well as the downstream targets of hedgehog signaling, were examined using surgically-excised KCOT tissues. PTCH1 mutations, including four novel ones, were found in 9 hereditary KCOT patients, but not in sporadic KCOT patients. A pathogenic mutation of PTCH2 or SUFU was not found in any patients. LOH at PTCH1 and SUFU loci correlated with the presence of epithelial budding. KCOT harboring a germline mutation (Type 1) showed nuclear localization of GLI2 and frequent histological findings such as budding and epithelial islands, as well as the highest recurrence rate. KCOT with LOH but without a germline mutation (Type 2) less frequently showed these histological features, and the recurrence rate was lower. KCOT with neither germline mutation nor LOH (Type 3) consisted of two subgroups, Type 3A and 3B, which were characterized by nuclear and cytoplasmic GLI2 localization, respectively. Type 3B rarely exhibited budding and recurrence, behaving as the most amicable entity. The expression patterns of CCND1 and BCL2 tended to correlate with these subgroups. Our data indicates a significant role of PTCH1 and SUFU in the pathogenesis of KCOT, and the genotype-oriented subgroups constitute entities with different potential aggressiveness.

Related: Signal Transduction

Fujii K, Ohashi H, Suzuki M, et al.
Frameshift mutation in the PTCH2 gene can cause nevoid basal cell carcinoma syndrome.
Fam Cancer. 2013; 12(4):611-4 [PubMed] Related Publications
Nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant disorder characterized by developmental defects and tumorigenesis. The gene responsible for NBCCS is PTCH1, encoding a receptor for the secreted protein, sonic hedgehog. Recently, a Chinese family with NBCCS carrying a missense mutation in PTCH2, a close homolog of PTCH1, was reported. However, the pathological significance of missense mutations should be discussed cautiously. Here, we report a 13-year-old girl diagnosed with NBCCS based on multiple keratocystic odontogenic tumors and rib anomalies carrying a frameshift mutation in the PTCH2 gene (c.1172_1173delCT). Considering the deleterious nature of the frameshift mutation, our study further confirmed a causative role for the PTCH2 mutation in NBCCS. The absence of typical phenotypes in this case such as palmar/plantar pits, macrocephaly, falx calcification, hypertelorism and coarse face, together with previously reported cases, suggested that individuals with NBCCS carrying a PTCH2 mutation may have a milder phenotype than those with a PTCH1 mutation.

Related: Basal Cell Nevus Syndrome (Gorlin Syndrome)

Jorgensen TJ, Ruczinski I, Yao Shugart Y, et al.
A population-based study of hedgehog pathway gene variants in relation to the dual risk of basal cell carcinoma plus another cancer.
Cancer Epidemiol. 2012; 36(5):e288-93 [PubMed] Free Access to Full Article Related Publications
INTRODUCTION: A personal history of basal cell carcinoma (BCC) is associated with increased risk of other malignancies, but the reason is unknown. The hedgehog pathway is critical to the etiology of BCC, and is also believed to contribute to susceptibility to other cancers. This study tested the hypothesis that hedgehog pathway and pathway-related gene variants contribute to the increased risk of subsequent cancers among those with a history of BCC.
METHODS: The study was nested within the ongoing CLUE II cohort study, established in 1989 in Washington County, Maryland, USA. The study consisted of a cancer-free control group (n=2296) compared to three different groups of cancer cases ascertained through 2007, those diagnosed with: (1) Other (non-BCC) cancer only (n=2349); (2) BCC only (n=534); and (3) BCC plus other cancer (n=446). The frequencies of variant alleles were compared among these four groups for 20 single nucleotide polymorphisms (SNPs) in 6 hedgehog pathway genes (SHH, IHH, PTCH2, SMO, GLI1, SUFU), and also 22 SNPs in VDR and 8 SNPs in FAS, which have cross-talk with the hedgehog pathway.
RESULTS: Comparing those with both BCC and other cancer versus those with no cancer, no significant associations were observed for any of the hedgehog pathway SNPs, or for the FAS SNPs. One VDR SNP was nominally significantly associated with the BCC cancer-prone phenotype, rs11574085 [per minor allele odds ratio (OR) 1.38, 95% confidence interval (CI) 1.05-1.82; p-value=0.02].
CONCLUSION: The hedgehog pathway gene SNPs studied, along with the VDR and FAS SNPs studied, are not strongly associated with the BCC cancer-prone phenotype.

Related: TNFRSF6 gene Basal Cell Carcinoma Skin Cancer

Pignot G, Vieillefond A, Vacher S, et al.
Hedgehog pathway activation in human transitional cell carcinoma of the bladder.
Br J Cancer. 2012; 106(6):1177-86 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: The Hedgehog (Hh) signalling pathway functions as an organiser in embryonic development. Recent studies have shown constitutive activation of this pathway in various malignancies, but its role in bladder cancer remains poorly studied.
METHODS: Expression levels of 31 genes and 9 microRNAs (miRNAs) involved in the Hh pathway were determined by quantitative real-time RT-PCR in 71 bladder tumour samples (21 muscle-invasive (MIBC) and 50 non-muscle-invasive (NMIBC) bladder cancers), as well as in 6 bladder cancer cell lines.
RESULTS: The SHH ligand gene and Gli-inducible target genes (FOXM1, IGF2, OSF2, H19, and SPP1) were overexpressed in tumour samples as compared with normal bladder tissue. SHH overexpression was found in 96% of NMIBC and 52% of MIBC samples, as well as in two bladder cancer cell lines. Altered expression of miRNAs supported their oncogene or tumour-suppressor gene status. In univariate analysis, high expression levels of PTCH2, miRNA-92A, miRNA-19A, and miRNA-20A were associated with poorer overall survival in MIBC (P=0.02, P=0.012, P=0.047, and P=0.036, respectively).
CONCLUSION: We observed constitutive activation of the Hh pathway in most NMIBC and about 50% of MIBC. We also found that some protein-coding genes and miRNAs involved in the Hh pathway may have prognostic value at the individual level.

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

Chaudary N, Pintilie M, Hedley D, et al.
Hedgehog pathway signaling in cervical carcinoma and outcome after chemoradiation.
Cancer. 2012; 118(12):3105-15 [PubMed] Related Publications
BACKGROUND: Hedgehog (Hh) signaling was assessed in patients with primary cervical carcinoma who were receiving chemoradiation. Because the up-regulation of Hh has been reported in response to hypoxia, the authors examined associations between Hh gene expression and measurements of HP5 (the percentage of oxygen pressure readings in each tumor <5 mm Hg) and interstitial fluid pressure (IFP).
METHODS: Sonic hedgehog (SHH), Indian hedgehog (IHH), patched 1 and 2 (PTCH1 and PTCH2), smoothened (SMO), and glioma-associated oncogene family zinc finger 1 (Gli1) expression levels were determined using quantitative reverse transcriptase-polymerase chain reaction analysis on 85 frozen samples of primary cervical carcinoma and on 16 normal cervical samples. Clinicopathologic data were collected prospectively. Possible correlations between Hh expression and tumor hypoxia (HP5 and IFP) measured at the time of biopsy, the time to local recurrence, and disease-free survival (DFS) were examined.
RESULTS: At least 1 member of the Hh pathway was elevated in all but 1 tumor compared with normal tissue (P < .0001). Hh gene expression was heterogeneous with SHH, IHH, and GLI exhibiting bimodal distribution. Elevation of SHH expression (P = .04) and low SMO expression (P = .0007) were associated with HP5. The risk of local recurrence was associated with the up-regulation of SMO (hazard ratio [HR], 2.41; 95% confidence interval [CI], 1.00-5.82; P = .044), the up-regulation of >3 Hh genes (HR, 2.56; 95% CI, 1.09-6.00; P = .026), tumor size (HR, 1.41; 95% CI, 1.14-1.74; P = .0015), and lymph node-positive disease (HR, 2.82; 95% CI, 1.16-6.86; P = .022).
CONCLUSIONS: The proportion of tumors that expressed Hh genes in cervical cancer was very high. The current data support a role for the Hh pathway in repopulation after chemoradiation and suggest that SMO may be a valid therapeutic target. The authors concluded that further investigation into this pathway after radiation and Hh inhibition are warranted.

Related: Signal Transduction Cervical Cancer

Santos DC, Zaphiropoulos PG, Neto CF, et al.
PTCH1 gene mutations in exon 17 and loss of heterozygosity on D9S180 microsatellite in sporadic and inherited human basal cell carcinomas.
Int J Dermatol. 2011; 50(7):838-43 [PubMed] Related Publications
BACKGROUND: Basal cell carcinomas (BCCs) are the most frequent human cancer that results from malignant transformation of basal cells in the epidermis. Gorlin syndrome is a rare inherited autosomal dominant disease that predisposes with multiple BCCs and other birth defects. Both sporadic and inherited BCCs are associated with mutations in the tumor suppressor gene PTCH1, but there is still uncertainty on the role of its homolog PTCH2.
OBJECTIVES: To search for mutations and genomic instability in sporadic and inherited BCCs.
METHODS: DNA obtained from leukocytes and tumor cells was amplified by polymerase chain reaction regarding five exons of PTCH1 and PTCH2 and neighboring microsatellites. Exons were sequenced and compared with the GenBank database.
RESULTS: Only D9S180, of six microsatellites, showed loss of heterozygosity in three BCCs (two sporadic and one inherited). One sporadic BCC presented the mutation g.2885G>C in exon 17 of PTCH1, which predicts the substitution p.R962T in an external domain of the protein. In addition, the leukocytes and tumor cells of one patient with Gorlin syndrome showed the mutation g.2839T>G in the same exon and gene, which predicts a p.E947stop and truncated protein. All control and tumor samples presented IVS9 + 217T in intron 9 of PTCH1.
CONCLUSION: Mutations found in the PTCH1 gene and neighboring repetitive sequences may have contributed to the development of the studied BCCs.

Related: Basal Cell Nevus Syndrome (Gorlin Syndrome) Basal Cell Carcinoma Skin Cancer

Katoh Y, Katoh M
Hedgehog target genes: mechanisms of carcinogenesis induced by aberrant hedgehog signaling activation.
Curr Mol Med. 2009; 9(7):873-86 [PubMed] Related Publications
Hedgehog signaling is aberrantly activated in glioma, medulloblastoma, basal cell carcinoma, lung cancer, esophageal cancer, gastric cancer, pancreatic cancer, breast cancer, and other tumors. Hedgehog signals activate GLI family members via Smoothened. RTK signaling potentiates GLI activity through PI3K-AKT-mediated GSK3 inactivation or RAS-STIL1-mediated SUFU inactivation, while GPCR signaling to Gs represses GLI activity through adenylate cyclase-mediated PKA activation. GLI activators bind to GACCACCCA motif to regulate transcription of GLI1, PTCH1, PTCH2, HHIP1, MYCN, CCND1, CCND2, BCL2, CFLAR, FOXF1, FOXL1, PRDM1 (BLIMP1), JAG2, GREM1, and Follistatin. Hedgehog signals are fine-tuned based on positive feedback loop via GLI1 and negative feedback loop via PTCH1, PTCH2, and HHIP1. Excessive positive feedback or collapsed negative feedback of Hedgehog signaling due to epigenetic or genetic alterations leads to carcinogenesis. Hedgehog signals induce cellular proliferation through upregulation of N-Myc, Cyclin D/E, and FOXM1. Hedgehog signals directly upregulate JAG2, indirectly upregulate mesenchymal BMP4 via FOXF1 or FOXL1, and also upregulate WNT2B and WNT5A. Hedgehog signals induce stem cell markers BMI1, LGR5, CD44 and CD133 based on cross-talk with WNT and/or other signals. Hedgehog signals upregulate BCL2 and CFLAR to promote cellular survival, SNAI1 (Snail), SNAI2 (Slug), ZEB1, ZEB2 (SIP1), TWIST2, and FOXC2 to promote epithelial-to-mesenchymal transition, and PTHLH (PTHrP) to promote osteolytic bone metastasis. KAAD-cyclopamine, Mu-SSKYQ-cyclopamine, IPI-269609, SANT1, SANT2, CUR61414 and HhAntag are small-molecule inhibitors targeted to Smoothened, GANT58, GANT61 to GLI1 and GLI2, and Robot-nikinin to SHH. Hedgehog signaling inhibitors should be used in combination with RTK inhibitors, GPCR modulators, and/or irradiation for cancer therapy.

Related: Cancer Prevention and Risk Reduction Signal Transduction

Hameed O, Perry A, Banerjee R, et al.
Papillary carcinoma of the breast lacks evidence of RET rearrangements despite morphological similarities to papillary thyroid carcinoma.
Mod Pathol. 2009; 22(9):1236-42 [PubMed] Related Publications
Rare breast neoplasms resembling the tall-cell variant of papillary thyroid carcinoma have been reported. In addition, papillary carcinoma of the breast occasionally displays nuclear features reminiscent of papillary thyroid carcinoma. In this study, we evaluated 33 intraductal/intracystic papillary carcinomas of the breast for the presence and extent of nuclear overlap, grooves, clearing, and inclusions, as well as features of the tall-cell or columnar-cell variants of papillary thyroid carcinoma. RET rearrangements were assessed in a subset of these cases. Paired probes localizing to the centromeric and telomeric ends of the RET gene on chromosome 10 were used for FISH using a break-apart approach. Single round and nested PCR was performed to detect RET/PTC1, RET/PTC2, RET/PTC3 and ELKS-RET fusion transcripts. Nuclear overlap, grooves, stratification, and clearing were identified in 24 (73%), 14 (42%), 11 (33%), and 9 (27%) cases respectively, whereas nuclear inclusions and 'tall-cell' features were each seen in only one (3%) and two (6%) cases, respectively. Four of 19 tested cases displayed split FISH signals in a low percentage of cells and were considered borderline for RET rearrangement. All 19 tested cases with amplifiable RNA were negative for the four RET fusion transcripts evaluated by RT-PCR. Although papillary carcinomas of breast often display one or more cytoarchitectural features of papillary thyroid carcinoma, there is no evidence that RET rearrangements are involved.

Related: Breast Cancer Male Breast Cancer FISH Thyroid Cancer TRIM27 gene

Li TJ, Sun LS, Luo HY, et al.
[Studies on keratocystic odontogenic tumors].
Beijing Da Xue Xue Bao. 2009; 41(1):16-20 [PubMed] Related Publications
Keratocystic odontogenic tumors (KCOTs, previously known as odontogenic keratocysts) are aggressive, noninflammatory jaw lesions with a putative high growth potential and a propensity for recurrence. This article puts together a summary of the serial studies related to KCOTs undertaken by the author's research group in recent years. Intraosseous jaw cysts with a solely orthokeratinized lining epithelium have been suggested to differ from the typical KCOTs. We report 20 cases of such cyst type under the term of 'orthokeratinized odontogenic cyst (OOC)'. Apart from the presence of a keratinizing epithelial lining, the OOC lacks the other histological features of KCOT, exhibits little if any tendency to recur, has no apparent association with NBCCS, may be cured by simple enucleation, and may thus constitute its own clinical entity. Mutations in PTCH1 gene are responsible for NBCCS and are related in tumors associated with this syndrome. We have so far detected 26 PTCH1 mutations (2 mutations occurred twice) in 10 out of 34 (29.4%) sporadic and 14 out of 16 (87.5%) NBCCS-associated KCOTs. The 26 mutations consisted of 10 frameshift, 2 nonsense, 3 aberrant splicing, 4 in-frame insertion/deletion/ duplication and 7 missense mutations. Two missense mutations in PTCH2 were also detected in 2 out of 15 NBCCS related KCOT patients. By contrast, no pathogenic mutation was detected in SMO. Thus, our data, together with reports from other groups, indicate that defects of PTCH1 are involved in the pathogenesis of syndromic as well as sporadic KCOTs. The pathogenic role of PTCH2 requires further investigation. A series of in vitro studies on bone resorption of KCOTs and ameloblastomas were undertaken by this group. The results indicate that odontogenic lesions could promote bone resorption in vitro and it is likely to be related to some of the cytokines secreted by the lesions.

Erdoğan M, Berdeli A, Karadeniz M, et al.
The prevalence of RET/PTC mutations in papillary thyroid cancers in Turkish population and its relation between tumor histopathology and prognostic factors.
Exp Clin Endocrinol Diabetes. 2008; 116(4):225-30 [PubMed] Related Publications
OBJECTIVE: In recent years, thyroid cancer has been at the forefront of molecular pathology as a result of the consequences of the Chernobyl disaster and the recognition of the role of RET/PTC rearrangements in papillary thyroid carcinomas (PTCs). Correlation of RET/PTC expression with clinical outcome is controversial. This study aims to identify the prevalence of RET/PTC oncogene expression in Turkey, and to investigate the correlation between RET/PTC oncogene expression and the known prognostic factors of PTC in 101 patients.
METHODS: The RET rearrangements were examined by means of reverse transcriptase-polymerase chain reaction analysis, with primers flanking the chimeric region. Statistical evaluation was performed by using Independent samples t-test, One-sample Chi-square test and Pearson Chi-square or Fisher's Exact Test.
RESULTS: RET/PTC was determined positive in 67(66.3%) of totally 101 patients (p<0.001). RET/PTC1 in 32(31.7%), RET/PTC3 in 21(20.8%), RET/PTC1+RET/PTC3 both in 10(9.9%) patients were found to be positive. There was RET/PTC2 positiveness in two patients, RET/PTC2,3 positiveness in one patient, and RET/PTC1,2,3 positiveness in one patient. No statistical difference was found between RET/PTC1 and RET/PTC3. None of genetico-clinical analyses showed any significant association between RET/PTC expression and the clinical and pathological features of the cancers.
CONCLUSION: While this prevalence of the RET/PTC is less than RET/PTC frequency seen after Chernobyl in Belarus, its prevalence in our region is also high (66.3%). As a result, no significant correlation was found in between prognosis and RET/PTC frequency.

Related: RET Thyroid Cancer

Fan Z, Li J, Du J, et al.
A missense mutation in PTCH2 underlies dominantly inherited NBCCS in a Chinese family.
J Med Genet. 2008; 45(5):303-8 [PubMed] Related Publications
BACKGROUND: Naevoid basal cell carcinoma syndrome (NBCCS) is a pleiotropic, autosomal dominant disease. Growing evidence suggests that the disorder may result from mutations in genes of the Sonic hedgehog (Shh) signalling pathway.
OBJECTIVE: To investigate the pathogenic gene in a Chinese Han family with NBCCS.
METHODS: Mapping and mutation screening were used to investigate the candidate genes SHH, PTCH, PTCH2 and SMO. A GLI1 reporter gene and a cell growth curve were used to examine functional consequences of the detected mutant.
RESULTS: One novel mutation, a G-->A transition (2157G-->A) in exon 15 of the PTCH2 gene, was identified in this family with NBCCS by direct sequencing and digestion with the AvaI restriction enzyme. The mutation was not found in normal family members or in 520 controls. The mutation led to an R719Q amino acid substitution in an extracellular loop of the PTCH2 protein. Functional studies revealed that the R719Q mutation resulted in inactivation of PTCH2 inhibitory activities. In contrast to wild type PTCH2, PTCH2-R719Q could not inhibit cell proliferation.
CONCLUSION: PTCH2 (2157G-->A), a novel missense mutation, underlies NBCCS, resulting in the loss of PTCH2 inhibitory function in the Shh signalling pathway.

Related: Basal Cell Nevus Syndrome (Gorlin Syndrome) Signal Transduction

Xu LL, Li TJ
[PTCH2 gene alterations in keratocystic odontogenic tumors associated with nevoid basal cell carcinoma syndrome].
Beijing Da Xue Xue Bao. 2008; 40(1):15-8 [PubMed] Related Publications
OBJECTIVE: To investigate alterations in PTCH2 in keratocystic odontogenic tumors (KCOT) associated with nevoid basal cell carcinoma syndrome (NBCCS).
METHODS: Genomic DNA was extracted from samples of frozen lesion tissues and peripheral blood of 15 NBCCS patients with multiple KCOTs. PTCH2 mutations were detected by PCR-direct sequencing.
RESULTS: 2 novel missence mutations(c.323 T>C,c.1319 C>T)of PTCH2 were identified and 9 polymorphisms (3 of which were novel) were determined in the present series.
CONCLUSION: Although not as frequent as PTCH1 mutations, PTCH2 germline mutations were detectable in a subset of NBCCS patients with KCOTs. The pathogenetic role of these PTCH2 mutations is yet to be clarified.

Related: Basal Cell Nevus Syndrome (Gorlin Syndrome)

Lee Y, Kawagoe R, Sasai K, et al.
Loss of suppressor-of-fused function promotes tumorigenesis.
Oncogene. 2007; 26(44):6442-7 [PubMed] Related Publications
The Sonic Hedgehog (SHH) signaling pathway is indispensable for development, and functions to activate a transcriptional program modulated by the GLI transcription factors. Here, we report that loss of a regulator of the SHH pathway, Suppressor of Fused (Sufu), resulted in early embryonic lethality in the mouse similar to inactivation of another SHH regulator, Patched1 (Ptch1). In contrast to Ptch1+/- mice, Sufu+/- mice were not tumor prone. However, in conjunction with p53 loss, Sufu+/- animals developed tumors including medulloblastoma and rhabdomyosarcoma. Tumors present in Sufu+/-p53-/- animals resulted from Sufu loss of heterozygosity. Sufu+/-p53-/- medulloblastomas also expressed a signature gene expression profile typical of aberrant SHH signaling, including upregulation of N-myc, Sfrp1, Ptch2 and cyclin D1. Finally, the Smoothened inhibitor, hedgehog antagonist, did not block growth of tumors arising from Sufu inactivation. These data demonstrate that Sufu is essential for development and functions as a tumor suppressor.

Related: Apoptosis Childhood Medulloblastoma / PNET Rhabdomyosarcoma TP53

Sasai K, Romer JT, Kimura H, et al.
Medulloblastomas derived from Cxcr6 mutant mice respond to treatment with a smoothened inhibitor.
Cancer Res. 2007; 67(8):3871-7 [PubMed] Related Publications
The sonic hedgehog (Shh) pathway is activated in approximately 30% of human medulloblastoma resulting in increased expression of downstream target genes. In about half of these cases, this has been shown to be a consequence of mutations in regulatory genes within the pathway, including Ptc1, Smo, and Sufu. However, for some tumors, no mutations have been detected in known pathway genes. This suggests that either mutations in other genes promote tumorigenesis or that epigenetic alterations increase pathway activity in these tumors. Here, we report that 3% to 4% of mice lacking either one or both functional copies of Cxcr6 develop medulloblastoma. Although CXCR6 is not known to be involved in Shh signaling, tumors derived from Cxcr6 mutant mice expressed Shh pathway target genes including Gli1, Gli2, Ptc2, and Sfrp1, indicating elevated pathway activity. Interestingly, the level of Ptc1 expression was decreased in tumor cells although two normal copies of Ptc1 were retained. This implies that reduced CXCR6 function leads to suppression of Ptc1 thereby increasing Smoothened function and promoting tumorigenesis. We used a direct transplant model to test the sensitivity of medulloblastoma arising in Cxcr6 mutant mice to a small-molecule inhibitor of Smoothened (HhAntag). We found that transplanted tumors were dramatically inhibited in mice treated for only 4 days with HhAntag. These findings suggest that HhAntag may be effective against tumors lacking mutations in known Shh pathway genes.

Related: Childhood Medulloblastoma / PNET

Katoh Y, Katoh M
Hedgehog signaling pathway and gastrointestinal stem cell signaling network (review).
Int J Mol Med. 2006; 18(6):1019-23 [PubMed] Related Publications
Hedgehog, BMP/TGFbeta, FGF, WNT and Notch signaling pathways constitute the stem cell signaling network, which plays a key role in a variety of processes, such as embryogenesis, maintenance of adult tissue homeostasis, tissue repair during chronic persistent inflammation, and carcinogenesis. Sonic hedgehog (SHH), Indian hedgehog (IHH) and Desert hedgehog (DHH) bind to PTCH1/PTCH or PTCH2 receptor to release Smoothened (SMO) signal transducer from Patched-dependent suppression. SMO then activates STK36 serine/threonine kinase to stabilize GLI family members and to phosphorylate SUFU for nuclear accumulation of GLI. Hedgehog signaling activation leads to GLI-dependent transcriptional activation of target genes, such as GLI1, PTCH1, CCND2, FOXL1, JAG2 and SFRP1. GLI1-dependent positive feedback loop combined with PTCH1-dependent negative feedback loop gives rise to transient proliferation of Hedgehog target cells. Iguana homologs (DZIP1 and DZIP1L) and Costal-2 homologs (KIF7 and KIF27) are identified by comparative integromics. SHH-dependent parietal cell proliferation is implicated in gastric mucosal repair during chronic Helicobacter pylori infection. BMP-RUNX3 signaling induces IHH expression in surface differentiated epithelial cells of stomach and intestine. Hedgehog signals from epithelial cells then induces FOXL1-mediated BMP4 upregulation in mesenchymal cells. Hedgehog signaling is frequently activated in esophageal cancer, gastric cancer and pancreatic cancer due to transcriptional upregulation of Hedgehog ligands and epigenetic silencing of HHIP1/HHIP gene, encoding the Hedgehog inhibitor. However, Hedgehog signaling is rarely activated in colorectal cancer due to negative regulation by the canonical WNT signaling pathway. Hedgehog signaling molecules or targets, such as SHH, IHH, HHIP1, PTCH1 and GLI1, are applied as biomarkers for cancer diagnostics, prognostics and therapeutics. Small-molecule inhibitors for SMO or STK36 are suitable to be used for treatment of Hedgehog-dependent cancer.

Related: Signal Transduction Stomach Cancer Gastric Cancer

Lee Y, Miller HL, Russell HR, et al.
Patched2 modulates tumorigenesis in patched1 heterozygous mice.
Cancer Res. 2006; 66(14):6964-71 [PubMed] Related Publications
The sonic hedgehog (SHH) receptor Patched 1 (Ptch1) is critical for embryonic development, and its loss is linked to tumorigenesis. Germ line inactivation of one copy of Ptch1 predisposes to basal cell carcinoma and medulloblastoma in mouse and man. In many cases, medulloblastoma arising from perturbations of Ptch1 function leads to a concomitant up-regulation of a highly similar gene, Patched2 (Ptch2). As increased expression of Ptch2 is associated with medulloblastoma and other tumors, we investigated the role of Ptch2 in tumor suppression by generating Ptch2-deficient mice. In striking contrast to Ptch1-/- mice, Ptch2-/- animals were born alive and showed no obvious defects and were not cancer prone. However, loss of Ptch2 markedly affected tumor formation in combination with Ptch1 haploinsufficiency. Ptch1+/-Ptch2-/- and Ptch1+/-Ptch2+/- animals showed a higher incidence of tumors and a broader spectrum of tumor types compared with Ptch1+/- animals. Therefore, Ptch2 modulates tumorigenesis associated with Ptch1 haploinsufficiency.

Related: Childhood Medulloblastoma / PNET Soft Tissue Sarcomas

Shakhova O, Leung C, van Montfort E, et al.
Lack of Rb and p53 delays cerebellar development and predisposes to large cell anaplastic medulloblastoma through amplification of N-Myc and Ptch2.
Cancer Res. 2006; 66(10):5190-200 [PubMed] Related Publications
Medulloblastomas are among the most common malignant brain tumors in childhood. They typically arise from neoplastic transformation of granule cell precursors in the cerebellum via deregulation of molecular pathways involved in normal cerebellar development. In a mouse model, we show here that impairment of the balance between proliferation and differentiation of granule cell precursors in the external granular layer of the developing cerebellum predisposes but is not sufficient to induce neoplastic transformation of these progenitor cells. Using array-based chromosomal comparative genomic hybridization, we show that genetic instability resulting from inactivation of the p53 pathway together with deregulation of proliferation induced by Rb loss eventually leads to neoplastic transformation of these cells by acquiring additional genetic mutations, mainly affecting N-Myc and Ptch2 genes. Moreover, we show that p53 loss influences molecular mechanisms that cannot be mimicked by the loss of either p19(ARF), p21, or ATM.

Related: Apoptosis Childhood Medulloblastoma / PNET RB1 TP53

Brzeziańska E, Karbownik M, Migdalska-Sek M, et al.
Molecular analysis of the RET and NTRK1 gene rearrangements in papillary thyroid carcinoma in the Polish population.
Mutat Res. 2006; 599(1-2):26-35 [PubMed] Related Publications
Among different genetic factors involved in the pathogenesis of the papillary thyroid carcinoma (PTC), rearrangements of RET protooncogene (RET/PTC), as well as rearrangements of NTRK1 protooncogene are best known. The resulting hybrid oncogenes are found in PTCs with variable frequency, depending on the examined population. The relationship between these chromosomal aberrations and clinical outcome of PTCs remains still controversial. The study aimed at estimating the frequency of rearrangements of RET and/or NTRK1 protooncogenes in PTC in the Polish population, and at evaluating the possible relationships between the presence of RET and/or NTRK1 oncogenes and such parameters, as patient's age, gender, histopathological variant of tumor and clinical staging. Expression analysis of RET and NTRK1 was performed by duplex reverse transcription-polymerase chain reaction (duplex RT-PCR) and OneStep RT-PCR, respectively, in tumor tissues obtained from 33 patients with PTC. Rearrangements of the RET protooncogene (RET/PTC1, RET/PTC2 and RET/PTC3) were detected in 7 out of 33 PTC (21%), and rearrangements of NTRK1 [Trk-T1 and Trk(TPM3)] were detected in 4 out of 33 examined samples (12%). In none of the examined cases, did the RET and NTRK1 rearrangements occur in the same sample. No correlations were found between RET/PTC or Trk oncogenic sequences and patient's age, gender, the histopathological variant of PTC and the assignment to particular stage in clinical staging systems (TNM Staging, the University of Chicago clinical class, and Ohio State University Staging). Our study is the first one in which the frequency of NTRK1 rearrangements in PTC was reported for the Polish population. On the other hand, the frequency of RET rearrangements in PTC, as found by us, was similar to the previously reported results for the Polish population. Our results do not confirm the relationship between the structural aberrations in question and the clinical outcome of PTC.

Related: RET NTRK1 gene Thyroid Cancer

Katoh Y, Katoh M
Hedgehog signaling pathway and gastric cancer.
Cancer Biol Ther. 2005; 4(10):1050-4 [PubMed] Related Publications
Hedgehog, WNT, FGF and BMP signaling pathways network together during embryogenesis, tissue regeneration, and carcinogenesis. Aberrant activation of Hedgehog signaling pathway leads to pathological consequences in a variety of human tumors, such as gastric cancer and pancreatic cancer. Endoscopic mucosal resection (EMR), endoscopic submucosal dissection (ESD), surgical gastrectomy and chemotherapy are therapeutic options for gastric cancer; however, prognosis of advanced gastric cancer patient is still poor. Here, Hedgehog signaling pathway in human gastric cancer and its clinical applications will be reviewed. Human SHH, IHH, DHH (Hedgehog homologs), HHAT (Hedgehog acyltransferase), HHIP (Hedgehog-interacting protein), DISP1, DISP2, DISP3 (Dispatched homologs), PTCH1, PTCH2 (Patched homologs), SMO (Smoothened homolog), KIF27, KIF7 (Costal-2 homologs), STK36 (Fused homolog), SUFU (SuFu homolog), DZIP1 (Iguana homolog), GLI1, GLI2 and GLI3 (Cubitus interruptus homologs) are implicated in the Hedgehog signaling. PTCH1, FOXM1 and CCND2 are direct transcriptional targets of Hedgehog signaling. Hedgehog signaling activation leads to cell proliferation through cell cycle regulation. SHH regulates growth and differentiation within gastric mucosa through autocrine loop and FOXL1-mediated epithelial-mesenchymal interaction. SHH is implicated in stem/progenitor cell restitution of damaged gastric mucosa during chronic infection with Helicobacter pylori. SHH up-regulation, IHH upregulation and HHIP down-regulation lead to aberrant activation of Hedgehog signaling through PTCH1 to GLI1 in gastric cancer. Small molecule compounds targeted to SMO (KADD-cyclopamine, SANT1-4, Cur61414) as well as humanized anti-SHH antibodies are potent anti-cancer drugs for gastric cancer. Cocktail of Hedgehog inhibitors would be developed as novel therapeutics for gastric cancer. Single nucleotide polymorphism (SNP) and copy number polymorphism (CNP) of Hedgehog signaling genes would be utilized for genetic screening of gastric cancer, while cDNA-PCR, microarray and ELISA detecting aberrant Hedgehog signaling activation would be utilized for therapeutic optional choice. Genetic screening and precise selection of therapeutic options would contribute to the realization of personalized medicine.

Related: Signal Transduction Stomach Cancer Gastric Cancer

Liu RT, Chou FF, Wang CH, et al.
Low prevalence of RET rearrangements (RET/PTC1, RET/PTC2, RET/PTC3, and ELKS-RET) in sporadic papillary thyroid carcinomas in Taiwan Chinese.
Thyroid. 2005; 15(4):326-35 [PubMed] Related Publications
Somatic rearrangement of the tyrosine kinase receptor RET is restricted to papillary thyroid carcinoma (PTC). The prevalence of RET/PTC1, RET/PTC2, and RET/PTC3 has been found to vary between 0% and 20% in most series of sporadic (nonradiation-induced) PTCs analyzed by type-specific reverse transcription-polymerase chain reaction (RT-PCR) alone. However, high prevalence reported from Taiwan (6 out of 11, 55%) indicates RET rearrangement is an important genetic lesion underlying the development of PTC in Taiwan. Because the high prevalence of RET rearrangements in Chinese patients was particularly striking, we were prompted to reexamine chimeric transcripts of RET/PTC1, RET/PTC2, and RET/PTC3 using the same experimental designs in a larger number of cases in the same population. RT-PCR was performed to amplify fusion products of RET/PTC1, RET/PTC2, RET/PTC3, and ELKS-RET from frozen tissue of 105 sporadic PTCs. RT-PCR was also performed with two different primer sets for RET/PTC1, RET/PTC2, and RET/PTC3 followed by Southern hybridization in the first 62 tumors. In our study, RET/PTC1, RET/PTC2, and RET/PTC3 oncogenes were found in only 7 of 105 (7%) sporadic PTCs. Of these tumors, 3 involved RET/PTC1 and 4 involved RET/PTC3. No RET/PTC2 rearrangements were observed. In the first 62 tumor samples, another two different primer sets for each rearrangement also gave concordant results. Furthermore, application of Southern hybridization in these 62 PTCs did not identify additional tumor harboring RET chimeric transcripts. We identified one tumor as having an ELKS-RET rearrangement (1 of 105, 1%). In conclusion, we detected RET rearrangements in 8 of 105 (8%) sporadic PTCs in Taiwan, a much lower prevalence than previously reported for this population but comparable to those reported in other nations using similar methodology. RET chimeric oncogenes only account for a small fraction of PTCs in Taiwan.

Related: BRAF gene RET Thyroid Cancer ELKS gene

Zakrzewska M, Rieske P, Debiec-Rychter M, et al.
Molecular abnormalities in pediatric embryonal brain tumors--analysis of loss of heterozygosity on chromosomes 1, 5, 9, 10, 11, 16, 17 and 22.
Clin Neuropathol. 2004 Sep-Oct; 23(5):209-17 [PubMed] Related Publications
Embryonal tumors, the most common group of malignant brain tumors in childhood, are heterogeneous and have been associated with a large number of genetic abnormalities. The aim of this study was to comprehensively analyze loss of heterozygosity (LOH) on regions harboring suppressor genes (PTCH2, PTCH1, APC, PTEN, DMBT1, SUFU, AXIN1, hSNF5/INI1) and to study chromosomal regions in which deletions have been described most frequently (1p, 1q, 11p, 16p, 17p). Twenty-nine children (17 male and 12 female), aged from 1 year 13 years were included in this study. There were 24 medulloblastomas (MB) and 5 supratentorial primitive neuroectodermal tumors (sPNET). Tissue samples from 29 primary and 11 recurrent tumors were analyzed according to the LOH standard procedures, which were extended to include fluorescence in situ hybridization for detection of isochromosome 17q (i(17q)) and direct sequencing ofTP53 exon 4. LOH on 17p was found in 15 out of 29 tumors. FISH analysis identified the presence of i(17q) in 16 tumors. Comparison of LOH analysis and the FISH data indicated that alterations of 17p were related to be the introduction of an i(17q) formation. LOH on 10q and 9q was observed in 4 and 2 cases, respectively, and was associated with alterations of chromosome 17. These results indicated a connection between alterations of PTCH/SHH genes and abnormalities of chromosome 17. A deleted region on 22q, covering the hSNF5/INI1 locus, was observed in 3 tumors. Progression of the molecular changes occurred in 1 case of recurrent medulloblastoma. LOH on 10q and 17p was found in both primary and recurrent tumor, while losses on 11p, 16p, and 16q occurred only in the recurrent tumor. No evidence of alteration in TP53 exon 4 was identified.

Related: Childhood Brain Tumours Childhood Brain Tumors FISH Germ Cell Tumors Germ Cell Tumours in Children and Young Adults Germ Cell Tumors (Pediatric)

Katoh Y, Katoh M
KIF27 is one of orthologs for Drosophila Costal-2.
Int J Oncol. 2004; 25(6):1875-80 [PubMed] Related Publications
Signals of Hedgehog family proteins (SHH, IHH and DHH) are transduced through Patched family receptors (PTCH1 and PTCH2) and Smoothened (SMO) to GLI family transcription factors (GLI1, GLI2 and GLI3). SHH plays a key role in development and progression of pancreatic cancer, gastric cancer, basal cell carcinoma, and brain tumors. Drosophila Costal-2 (Cos2) is implicated in the Hedgehog pathway through the interaction with Smoothened (Smo), Cubitus interruptus (Ci), Fused (Fu), and microtubule; however, mammalian ortholog of Drosophila Cos2 remained to be identified. Here we identified and characterized human ortholog of Drosophila Cos2 by using bioinformatics. Full-length Drosophila Cos2 was most homologous to human KIF27, followed by mouse Kif7, and other KIF family members. KIF27 gene at human chromosome 9q22.1 and KIF7 gene at human chromosome 15q26.1 were paralogs within the human genome. Phylogenetic analysis revealed that KIF27, Kif7, KIF4A, KIF4B and KIF21A constitute the KIF27 subfamily among mammalian Kinesin family. Drosophila Cos2 protein consists of Kinesin motor (KISc) domain, Ci-binding domain, and Smo-binding domain. KIF27 itself shared the common domain structure with Drosophila Cos2, while other members of KIF27 subfamily shared partial domain structure with Drosophila Cos2. These facts indicate that KIF27 is one of mammalian orthologs for Drosophila Cos2.

Related: Chromosome 15 Chromosome 9 Signal Transduction

Lévy P, Vidaud D, Leroy K, et al.
Molecular profiling of malignant peripheral nerve sheath tumors associated with neurofibromatosis type 1, based on large-scale real-time RT-PCR.
Mol Cancer. 2004; 3:20 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Neurofibromatosis type 1 (NF1) is an autosomal dominant disorder with a complex range of clinical symptoms. The hallmark of NF1 is the onset of heterogeneous (dermal or plexiform) benign neurofibromas. Plexiform neurofibromas can give rise to malignant peripheral nerve sheath tumors (MPNSTs), and the underlying molecular mechanisms are largely unknown.
RESULTS: To obtain further insight into the molecular pathogenesis of MPNSTs, we used real-time quantitative RT-PCR to quantify the mRNA expression of 489 selected genes in MPNSTs, in comparison with plexiform neurofibromas. The expression of 28 (5.7%) of the 489 genes was significantly different between MPNSTs and plexiform neurofibromas; 16 genes were upregulated and 12 were downregulated in MPNSTs. The altered genes were mainly involved in cell proliferation (MKI67, TOP2A, CCNE2), senescence (TERT, TERC), apoptosis (BIRC5/Survivin, TP73) and extracellular matrix remodeling (MMP13, MMP9, TIMP4, ITGB4). More interestingly, other genes were involved in the Ras signaling pathway (RASSF2, HMMR/RHAMM) and the Hedgehog-Gli signaling pathway (DHH, PTCH2). Several of the down-regulated genes were Schwann cell-specific (L1CAM, MPZ, S100B, SOX10, ERBB3) or mast cell-specific (CMA1, TPSB), pointing to a depletion and/or dedifferentiation of Schwann cells and mast cells during malignant transformation of plexiform neurofibromas.
CONCLUSION: These data suggest that a limited number of signaling pathways, and particularly the Hedgehog-Gli signaling pathway, may be involved in malignant transformation of plexiform neurofibromas. Some of the relevant genes or their products warrant further investigation as potential therapeutic targets in NF1.

Related: Apoptosis Signal Transduction Skin Cancer

Chung KW, Chang MC, Noh DY, et al.
RET oncogene expression of papillary thyroid carcinoma in Korea.
Surg Today. 2004; 34(6):485-92 [PubMed] Related Publications
PURPOSE: To identify the prevalence of RET/PTC oncogene expression in Korea, and to investigate the correlation between RET/PTC oncogene expression and the known prognostic factors of papillary thyroid carcinoma (PTC) in 22 patients.
METHODS: We performed reverse transcription-polymerase chain reaction (RT-PCR) for RET/PTC1, RET/PTC2, and RET/PTC3 rearrangements and immunohistochemical staining for the RET gene. Patient information was obtained from medical records. The chi(2) test, independent sample t-test, and logistic regression were used for statistical analysis.
RESULTS: The mean age of the patients was 44.4 years. RET/PTC rearrangement by RT-PCR was positive in only 2 (9.1%) of the 22 patients, and RET/PTC1 and RET/PTC3 were positive in 1 patient each (4.5%). Immunohistochemical staining revealed positive RET oncogene expression in 8 patients (36.3%). RET oncogene expression was marginally related to recurrence ( P = 0.05), but without significance by multivariate analysis.
CONCLUSION: It is possible that a rare form of rearrangement exists in Korean papillary thyroid carcinoma, but this study failed to prove that RET oncogene expression is associated with alleged prognostic factors.

Related: RET Thyroid Cancer

Sulman EP, White PS, Brodeur GM
Genomic annotation of the meningioma tumor suppressor locus on chromosome 1p34.
Oncogene. 2004; 23(4):1014-20 [PubMed] Related Publications
Meningioma is a frequently occurring tumor of the meninges surrounding the central nervous system. Loss of the short arm of chromosome 1 (1p) is the second most frequent chromosomal abnormality observed in these tumors. Previously, we identified a 3.7 megabase (Mb) region of consistent deletion on 1p33-p34 in a panel of 157 tumors. Loss of this region was associated with advanced disease and predictive for tumor relapse. In this report, a high-resolution integrated map of the region was constructed (CompView) to identify all markers in the smallest region of overlapping deletion (SRO). A regional somatic cell hybrid panel was used to more precisely localize those markers identified in CompView as within or overlapping the region. Additional deletion mapping using microsatellites localized to the region narrowed the SRO to approximately 2.8 Mb. The 88 markers remaining in the SRO were used to screen genomic databases to identify large-insert clones. Clones were assembled into a physical map of the region by PCR-based, sequence-tagged site (STS) content mapping. A sequence from clones was used to validate STS content by electronic PCR and to identify transcripts. A minimal tiling path of 43 clones was constructed across the SRO. Sequence data from the most current sequence assembly were used for further validation. A total of 59 genes were ordered within the SRO. In all, 17 of these were selected as likely candidates based on annotation using Gene Ontology Consortium terms, including the MUTYH, PRDX1, FOXD2, FOXE3, PTCH2, and RAD54L genes. This annotation of a putative tumor suppressor locus provides a resource for further analysis of meningioma candidate genes.

Related: Chromosome 1

Lee Y, Miller HL, Jensen P, et al.
A molecular fingerprint for medulloblastoma.
Cancer Res. 2003; 63(17):5428-37 [PubMed] Related Publications
Medulloblastoma is the most common malignant pediatric brain tumor. In mice, Ptc1 haploinsufficiency and disruption of DNA repair (DNA ligase IV inactivation) or cell cycle regulation (Kip1, Ink4d, or Ink4c inactivation), in conjunction with p53 dysfunction, predispose to medulloblastoma. To identify genes important for this tumor, we evaluated gene expression profiles in medulloblastomas from these mice. Unexpectedly, medulloblastoma expression profiles were very similar among tumors and also to those of developing cerebellum. However, 21 genes were specifically up-regulated in medulloblastoma, including sFrp1, Ptc2, and Math1, members of signaling pathways that regulate cerebellar development. Coordinated deregulation of these same genes also occurred in a large subset of human medulloblastomas. These data identify a group of genes that is central to medulloblastoma tumorigenesis.

Related: Childhood Medulloblastoma / PNET

Knauf JA, Kuroda H, Basu S, Fagin JA
RET/PTC-induced dedifferentiation of thyroid cells is mediated through Y1062 signaling through SHC-RAS-MAP kinase.
Oncogene. 2003; 22(28):4406-12 [PubMed] Related Publications
Constitutive activation of the RET proto-oncogene in papillary thyroid carcinomas results from rearrangements linking the promoter(s) and N-terminal domains of unrelated genes to the C-terminus of RET tyrosine kinase (RET/PTC). RET/PTC expression has been demonstrated to inhibit transcription of thyroid-specific genes. To study the signal transduction pathways responsible for this, we generated PCCL3 thyroid cells with doxycycline-inducible expression of RET/PTC3, RET/PTC3(Y541F), or PTC2/PDZ. Acute expression of RET/PTC(Y541F) appropriately interacted with Shc, an intermediate in the activation of the Ras pathway, but failed to activate PLCgamma. By contrast, PTC2/PDZ failed to bind Shc, but interacted normally with PLCgamma. Acute expression of RET/PTC3 or RET/PTC3(Y541F), but not PTC2/PDZ, inhibited TSH-induced Tg and NIS expression, suggesting that activation of Shc-Ras, but not PLCgamma, is required for RET/PTC-induced dedifferentiation. Accordingly, acute expression of H-Ras(V12) or of a constitutively active MEK1 also blocked TSH-induced expression of Tg and NIS. Moreover, MEK inhibitors restored Tg and NIS levels. In conclusion, activation of the Ras/Raf/MEK/MAPK pathway through Shc mediates RET/PTC-induced thyroid cell dedifferentiation. This suggests that inhibition of this pathway may promote redifferentiation in poorly differentiated thyroid carcinomas with constitutive activation of either Ras or RET/PTC.

Related: Signal Transduction Thyroid Cancer

Lam KY, Lo CY, Leung PS
High prevalence of RET proto-oncogene activation (RET/PTC) in papillary thyroid carcinomas.
Eur J Endocrinol. 2002; 147(6):741-5 [PubMed] Related Publications
OBJECTIVE: The activation of RET proto-oncogene, through different types of chromosomal translocation and inversion, is unique to papillary thyroid carcinomas (PTC) and its frequency is variable in different populations. The aim of this study was to investigate the frequency and types of PTC genetic rearrangements in papillary carcinoma in a population of Hong Kong Chinese.
METHODS: The presence of RET/PTC1, RET/PTC2 and RET/PTC3 activation was analyzed by RT-PCR in twenty PTC from adult patients (age range 24-63 years), one PTC from a 12-year-old boy and anaplastic carcinomas in two adult patients.
RESULTS: RET/PTC3 was the only activation of RET proto-oncogene identified in the samples. Seventeen PTC from adult patients (85%t) were positive for RET/PTC3. RET/PTC3 was also identified in PTC from the child and one of the two patients with anaplastic thyroid carcinoma.
CONCLUSIONS: The prevalence of RET/PTC activation in PTC is high and RET/PTC3 is the only type of activation identified in Hong Kong Chinese and is an important genetic event underlying the development of PTC in the population.

Related: RET Thyroid Cancer

Dicker AJ, Serewko MM, Russell T, et al.
Isolation (from a basal cell carcinoma) of a functionally distinct fibroblast-like cell type that overexpresses Ptch.
J Invest Dermatol. 2002; 118(5):859-65 [PubMed] Related Publications
In this study we report on the isolation and characterization of a nonepithelial, nontumorigenic cell type (BCC1) derived from a basal cell carcinoma from a patient. The BCC1 cells share many characteristics with dermal fibroblasts, such as the expression of vimentin, lack of expression of cytokeratins, and insensitivity to agents that cause growth inhibition and differentiation of epithelial cells; however, significant differences between BCC1 cells and fibroblasts also exist. For example, BCC1 cells are stimulated to undergo DNA synthesis in response to interferon-gamma, whereas dermal fibroblasts are not. More over, BCC1 cells overexpress the basal cell carcinoma-specific genes ptch and ptch2. These data indicate that basal cell carcinomas are associated with a functionally distinct population of fibroblast-like cells that overexpress known tumor-specific markers (ptch and ptch2).

Related: Basal Cell Carcinoma Skin Cancer Prevention of Skin Cancer Non-Melanoma Skin Cancer NMSC - Molecular Biology


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