Research IndicatorsGraph generated 31 August 2019 using data from PubMed using criteria.
Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic. Tag cloud generated 31 August, 2019 using data from PubMed, MeSH and CancerIndex
Specific Cancers (8)
Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.
Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).
OMIM, Johns Hopkin University
Referenced article focusing on the relationship between phenotype and genotype.
International Cancer Genome Consortium.
Summary of gene and mutations by cancer type from ICGC
Cancer Genome Anatomy Project, NCI
COSMIC, Sanger Institute
Somatic mutation information and related details
GEO Profiles, NCBI
Search the gene expression profiles from curated DataSets in the Gene Expression Omnibus (GEO) repository.
Latest Publications: IFNA2 (cancer-related)
Ma N, Zhang X, Yang L, et al.Role of Functional IFNL4, IFNLR1, IFNA, IFNAR2 Polymorphisms in Hepatitis B virus-related liver disease in Han Chinese population.
J Viral Hepat. 2018; 25(3):306-313 [PubMed
] Related Publications
Recent studies show that variants in some interferon genes together with interferon receptor genes are associated with the outcome of infectious diseases. We examined the association between the risk of hepatitis B virus (HBV)-related liver disease and the functional polymorphisms within IFNL4, IFNLR1, IFNA1, IFNA2, IFNA5 and IFNAR2 genes (14 loci in all) in a Han Chinese population. A total of 3128 people participated and were divided into 5 groups: healthy controls, natural clearance, chronic hepatitis B(CHB), liver cirrhosis and hepatocellular carcinoma (HCC). Significant associations were observed for 4 variants in IFNAR2, IFNLR1 with HBV infection, and IFNLR1-rs4649203 was associated with HBV recovery. Moreover, we demonstrated the clear relevance of 5 polymorphisms in IFNA1, IFNA2, IFNL4 with HCC. Three SNPs in IFNL4 gene may be important susceptible factors for the progression of HBV-related liver disease by trend chi-square test. The IFNL4 haplotype conformed by rs12971396_G, rs8113007_T and rs7248668A was more frequent in HCC than CHB and LC group. Three polymorphisms in the 5' region of the IFNL4 gene are associated with the progression of HBV-related liver disease. IFNA1- rs1831583 and IFNA2- rs649053 are associated with the development of HCC. IFNLR1- rs4649203, rs7525481 are predictors for HBV infection, and rs4649203 is a predictor of spontaneous clearance. IFNAR2 -rs1051393, rs12233338 may be predictive markers of HBV infection in the Chinese population.
Fragale A, Romagnoli G, Licursi V, et al.Antitumor Effects of Epidrug/IFNα Combination Driven by Modulated Gene Signatures in Both Colorectal Cancer and Dendritic Cells.
Cancer Immunol Res. 2017; 5(7):604-616 [PubMed
] Related Publications
Colorectal cancer results from the progressive accumulation of genetic and epigenetic alterations. IFN signaling defects play an important role in the carcinogenesis process, in which the inability of IFN transcription regulatory factors (IRF) to access regulatory sequences in IFN-stimulated genes (ISG) in tumors and in immune cells may be pivotal. We reported that low-dose combination of two FDA-approved epidrugs, azacytidine (A) and romidepsin (R), with IFNα2 (ARI) hampers the aggressiveness of both colorectal cancer metastatic and stem cells
Elias KM, Harvey RA, Hasselblatt KT, et al.Type I interferons modulate methotrexate resistance in gestational trophoblastic neoplasia.
Am J Reprod Immunol. 2017; 77(6) [PubMed
] Related Publications
PROBLEM: Resistance to methotrexate is a leading clinical problem in gestational trophoblastic neoplasia (GTN), but there are limited laboratory models for this condition.
METHOD OF STUDY: We created isogenic trophoblastic cell lines resistant to methotrexate and compared these to the parent cell lines using gene expression microarrays and qRT-PCR followed by mechanistic studies using recombinant cytokines, pathway inhibitors, and patient sera.
RESULTS: Gene expression microarrays and focused analysis by qRT-PCR revealed methotrexate led to type I interferon upregulation, in particular interferon alpha 2 (IFNA2), and methotrexate resistance was associated with chronic low level increases in type I interferon expression. Recombinant IFNA2 imparted chemosensitive choriocarcinoma cells with partial resistance to methotrexate, while chemoresistant choriocarcinoma cells were uniquely sensitive to fludarabine, a STAT1 inhibitor. In pre-treatment patient sera, IFNA2 levels correlated with subsequent resistance to methotrexate chemotherapy.
CONCLUSION: Methotrexate resistance is influenced by type I interferon signaling with prognostic and therapeutic implications for treating women with GTN.
Kaowinn S, Cho IR, Moon J, et al.Pancreatic adenocarcinoma upregulated factor (PAUF) confers resistance to pancreatic cancer cells against oncolytic parvovirus H-1 infection through IFNA receptor-mediated signaling.
Biochem Biophys Res Commun. 2015; 459(2):313-318 [PubMed
] Related Publications
Pancreatic adenocarcinoma upregulated factor (PAUF), a novel oncogene, plays a crucial role in the development of pancreatic cancer, including its metastasis and proliferation. Therefore, PAUF-expressing pancreatic cancer cells could be important targets for oncolytic virus-mediated treatment. Panc-1 cells expressing PAUF (Panc-PAUF) showed relative resistance to parvovirus H-1 infection compared with Panc-1 cells expressing an empty vector (Panc-Vec). Of interest, expression of type I IFN-α receptor (IFNAR) was higher in Panc-PAUF cells than in Panc-Vec cells. Increased expression of IFNAR in turn increased the activation of Stat1 and Tyk2 in Panc-PAUF cells compared with that in Panc-Vec cells. Suppression of Tyk2 and Stat1, which are important downstream molecules for IFN-α signaling, sensitized pancreatic cancer cells to parvovirus H-1-mediated apoptosis. Further, constitutive suppression of PAUF sensitized Bxpc3 pancreatic cancer cells to parvovirus H-1 infection. Taken together, these results suggested that PAUF conferred resistance to pancreatic cancer cells against oncolytic parvovirus H-1 infection through IFNAR-mediated signaling.
PURPOSE: IFNa was the first cytokine to demonstrate anti-tumor activity in advanced melanoma. Despite the ability of high-dose IFNa reducing relapse and mortality by up to 33%, large majority of patients experience side effects and toxicity which outweigh the benefits. The current study attempts to identify genetic markers likely to be associated with benefit from IFN-a2b treatment and predictive for survival.
EXPERIMENTAL DESIGN: We tested the association of variants in FOXP3 microsatellites, CTLA4 SNPs and HLA genotype in 284 melanoma patients and their association with prognosis and survival of melanoma patients who received IFNa adjuvant therapy.
RESULTS: Univariate survival analysis suggested that patients bearing either the DRB1*15 or HLA-Cw7 allele suffered worse OS while patients bearing either HLA-Cw6 or HLA-B44 enjoyed better OS. DRB1*15 positive patients suffered also worse RFS and conversely HLA-Cw6 positive patients had better RFS. Multivariate analysis revealed that a five-marker genotyping signature was prognostic of OS independent of disease stage. In the multivariate Cox regression model, HLA-B38 (p = 0.021), HLA-C15 (p = 0.025), HLA-C3 (p = 0.014), DRB1*15 (p = 0.005) and CT60*G/G (0.081) were significantly associated with OS with risk ratio of 0.097 (95% CI, 0.013-0.709), 0.387 (95% CI, 0.169-0.889), 0.449 (95% CI, 0.237-0.851), 1.948 (95% CI, 1.221-3.109) and 1.484 (95% IC, 0.953-2.312) respectively.
CONCLUSION: These results suggest that gene polymorphisms relevant to a biological occurrence are more likely to be informative when studied in concert to address potential redundant or conflicting functions that may limit each gene individual contribution. The five markers identified here exemplify this concept though prospective validation in independent cohorts is needed.
Mühleisen B, Petrov I, Frigerio S, et al.Pronounced allelic imbalance at D9S162 in skin squamous cell carcinoma of organ transplant recipients.
Arch Dermatol. 2012; 148(6):697-703 [PubMed
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OBJECTIVE: To evaluate chromosomal instability at 9p21-22 with p16 protein expression in organ transplant recipients (OTRs) compared with immunocompetent patients with squamous cell carcinoma (SCC).
DESIGN: In a select population of intraepithelial and subsequent invasive SCC from the same anatomic region of the same patient at different times, we assessed loss of heterozygosity at 3 microsatellites—IFNA, D9S162, and D9S925—in the course of carcinogenesis in OTRs and immunocompetent patients.
SETTING: Department of Dermatology, University Hospital Zurich.
PATIENTS: Immunocompetent patients and OTRs with SCC on sun-damaged skin.
MAIN OUTCOME MEASURE: Chromosomal allelic balance in SCC of OTRs and immunocompetent patients.
RESULTS: Reduced allelic balance at IFNA, D9S162, and D9S925 in intraepithelial forms of SCC and similar allelic imbalance in invasive forms of SCC were found. Allelic balance at D9S162 was reduced for SCC in OTRs compared with SCC in immunocompetent patients. The study revealed broadly reduced allelic balance at 9p21-22 in all cutaneous SCCs, and OTRs presented a further reduced allelic balance for D9S162, suggesting a common trait for SCC in OTRs. Actinic keratosis and Bowen disease differed in allelic balance at D9S162, suggesting substantial differences in their carcinogenesis.
CONCLUSION: Reduced allelic balance around locus D9S162 is a genomic correlate for enhanced carcinogenesis in OTRs.
Bi X, Yang L, Mancl ME, Barnes BJModulation of interferon regulatory factor 5 activities by the Kaposi sarcoma-associated herpesvirus-encoded viral interferon regulatory factor 3 contributes to immune evasion and lytic induction.
J Interferon Cytokine Res. 2011; 31(4):373-82 [PubMed
] Related Publications
Multiple Kaposi's sarcoma-associated herpesvirus (KSHV)-encoded proteins with potential roles in KSHV-associated neoplasms have been identified. KSHV encodes 4 genes with homology to transcription factors of the interferon (IFN) regulatory factor (IRF) family. Viral IRF3 (vIRF3) is expressed in latently KSHV-infected primary effusion lymphoma (PEL) cells and was recently shown to be essential for the survival of PEL cells. The focus of this study was to determine the mechanism(s) of vIRF3 oncogenic activity contributing to KSHV-associated lymphoma. We report that vIRF3 interacts with the amino-terminal DNA binding domain of human IRF5, leading to a complex manipulation of IRF5 function. vIRF3 associated with both exogenous and endogenous IRF5, thereby inhibiting IRF5-mediated IFN promoter activation and the synthesis of biologically active type I IFNs by blocking its binding to endogenous IFNA promoters. The function of this interaction was not limited to the IFN system as IRF5-mediated cell growth regulation was significantly altered by overexpression of vIRF3 in B cells. vIRF3 prevented IRF5-mediated growth inhibition and G2/M cell cycle arrest. Important, IRF5 was upregulated by the protein kinase C agonist 12-O-tetradecanoyl-phorbol-13-acetate in BCBL1 PEL cells and interaction with vIRF3 was observed at the endogenous p21 promoter in response to 12-O-tetradecanoyl-phorbol-13-acetate, suggesting that these 2 proteins cooperate in the regulation of lytic cycle-induced G1 arrest, which is an important early step for the reactivation of KSHV. In conclusion, cellular IRF5 and vIRF3 interact, leading to the functional modulation of IRF5-mediated type I IFN expression and cell cycle regulation. These findings support an important role for vIRF3 in immune evasion and cell proliferation that likely contribute to the survival of PEL cells.
Lopez-Beltran A, Amin MB, Oliveira PS, et al.Urothelial carcinoma of the bladder, lipid cell variant: clinicopathologic findings and LOH analysis.
Am J Surg Pathol. 2010; 34(3):371-6 [PubMed
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In this report, we present the clinicopathologic features of 27 cases of the lipid cell variant of urothelial bladder carcinoma. This is a rare variant of bladder cancer recognized by the current WHO classification of urologic tumors. The lipid cell component varied from 10% to 50% of the tumor specimen; in 11 cases the lipid cell component composed greater than 30% of the tumor. The architectural pattern of the tumor varied from solid expansile to infiltrative nests. The large epithelial tumor cells had an eccentrically placed nucleus and abundant vacuolated cytoplasm resembling signetring lipoblasts. Mucin stains were negative in all the cases. Typical features of high grade conventional urothelial carcinoma were present in all the cases with micropapillary or plasmacytoid carcinoma in 2 and 1 cases, respectively; extensive squamous or glandular differentiation was present in 2 additional cases. Most neoplastic cells had nuclei of intermediate nuclear grade with occasional nuclear pleomorphism. Immunohistochemical staining showed that the lipid cell component was positive for cytokeratins 7, 20, CAM 5.2, high molecular weight (34ssE12) and AE1/AE3, epithelial membrane antigen, and thrombomodulin; vimentin and S100 protein were negative. The loss of heterozygosity (LOH) analysis was done on 8 cases using 4 polymorphic microsatellite markers (D9S171, D9S177, IFNA, and TP 53); LOH at least in 1 marker was present in 6 cases. The LOH results were the same for lipid variant and conventional urothelial carcinoma. Pathologic stage was Ta (n=1), T1 (=2), T2, at least (n=7), T3a (n=4), T3b (n=8), and T4a (n=5). Electron microcopy analysis based on 2 cases supported lipid content in tumor cells. Follow-up information was available in all the cases, ranging from 6 to 58 months (mean, 28 mo). Sixteen of the patients died of disease at 16 to 58 months (mean, 33 mo) and 8 patients were alive with disease at 8 to 25 months (mean, 22 mo). Another 3 patients died of other causes at 6 to 15 months (mean, 10 mo). In summary, lipid cell urothelial bladder carcinoma is typically associated with advanced stage high-grade urothelial carcinoma, in which the prognosis is poor and clonally related to the concurrent conventional urothelial carcinoma. In limited samples, it may be misdiagnosed as liposarcoma, sarcomatoid carcinoma (carcinosarcoma), or signetring cell carcinoma. Morphologic distinction from other malignant neoplasms with lipid cell phenotype is critical for its clinical management.
Nacheva EP, Brazma D, Virgili A, et al.Deletions of immunoglobulin heavy chain and T cell receptor gene regions are uniquely associated with lymphoid blast transformation of chronic myeloid leukemia.
BMC Genomics. 2010; 11:41 [PubMed
] Free Access to Full Article Related Publications
BACKGROUND: Chronic myelogenous leukemia (CML) results from the neoplastic transformation of a haematopoietic stem cell. The hallmark genetic abnormality of CML is a chimeric BCR/ABL1 fusion gene resulting from the Philadelphia chromosome rearrangement t(9;22)(q34;q11). Clinical and laboratory studies indicate that the BCR/ABL1 fusion protein is essential for initiation, maintenance and progression of CML, yet the event(s) driving the transformation from chronic phase to blast phase are poorly understood.
RESULTS: Here we report multiple genome aberrations in a collection of 78 CML and 14 control samples by oligonucleotide array comparative genomic hybridization. We found a unique signature of genome deletions within the immunoglobulin heavy chain (IGH) and T cell receptor regions (TCR), frequently accompanied by concomitant loss of sequences within the short arm regions of chromosomes 7 and 9, including IKZF1, HOXA7, CDKN2A/2B, MLLT3, IFNA/B, RNF38, PAX5, JMJD2C and PDCD1LG2 genes.
CONCLUSIONS: None of these genome losses were detected in any of the CML samples with myeloid transformation, chronic phase or controls, indicating that their presence is obligatory for the development of a malignant clone with a lymphoid phenotype. Notably, the coincidental deletions at IGH and TCR regions appear to precede the loss of IKZF1 and/or p16 genes in CML indicating a possible involvement of RAG in these deletions.
Rouprêt M, Hupertan V, Yates DR, et al.A comparison of the performance of microsatellite and methylation urine analysis for predicting the recurrence of urothelial cell carcinoma, and definition of a set of markers by Bayesian network analysis.
BJU Int. 2008; 101(11):1448-53 [PubMed
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OBJECTIVE: To compare the potential of two diagnostic methods for detecting recurrence of urothelial cell carcinoma (UCC) of the bladder, by (i) detecting alterations in microsatellite DNA markers and loss of heterozygosity (LOH), and (ii) detecting aberrant gene hypermethylation, as UCC has a high recurrence rate in the urinary tract and the disease can invade muscle if new tumours are overlooked.
PATIENTS AND METHODS: Over 1 year, urine samples were retrieved from 40 patients already diagnosed with bladder UCC (30 pTa, two pTis, eight pT1). Samples were collected 6 months after bladder tumour resection, during the follow-up schedule. We used samples to analyse nine microsatellite markers and the methylation status of 11 gene promoters. Receiver operating characteristic curves were generated and Bayesian statistics used to create an interaction network between recurrence and the biomarkers.
RESULTS: During the study, 15 of the 40 patients (38%) had a tumour recurrence and 14 were identified by cystoscopy (reference method). Overall, microsatellite markers (area under curve, AUC 0.819, 95% confidence interval, CI, 0.677-0.961) had better performance characteristics than promoter hypermethylation (AUC 0.448, 0.259-0.637) for detecting recurrence. A marker panel of IFNA, MBP, ACTBP2, D9S162 and of RASSF1A, and WIF1 generated a higher diagnostic accuracy of 86% (AUC 0.92, 0.772-0.981).
CONCLUSION: Microsatellite markers have better performance characteristics than promoter hypermethylation for detecting UCC recurrence. These data support the further development of a combination of only six markers from both methods in urinary DNA. Once validated, it could be used routinely during the follow-up for the early detection and surveillance of UCC from the lower and upper urinary tract.
Katona TM, O'Malley DP, Cheng L, et al.Loss of heterozygosity analysis identifies genetic abnormalities in mycosis fungoides and specific loci associated with disease progression.
Am J Surg Pathol. 2007; 31(10):1552-6 [PubMed
] Related Publications
Mycosis fungoides (MF) exhibits a variety of underlying molecular defects. Loss of heterozygosity (LOH) is a technique used to detect chromosomal imbalances in neoplastic disorders using archival tissue. We analyzed skin biopsies of MF in different stages for the presence of LOH at specific loci to evaluate underlying genetic aberrations involved in MF and its progression. Twenty-five skin biopsies (15 plaque stage and 10 tumor stage) from 19 patients were evaluated. LOH was examined at 1p22 (D1S2766), 9p21 [IFNA, p15 (D9S1748), p16 (D9S171)], 10q23 [PTEN (D10S185, D10S541, D10S2491)], and 17p13 [p53 (TP53)]. Abnormal lymphocytes were microdissected from formalin-fixed, paraffin-embedded tissue sections. Sixteen of the 25 (64%) specimens evaluated had at least one abnormal LOH locus and LOH was identified in 7 of 15 (47%) plaque and in 9 of 10 (90%) tumor stage lesions, respectively. All 3 patients with sequential biopsies (plaque followed by tumor lesions) had additional LOH abnormalities in tumor specimens compared with plaque stage lesions. LOH most frequently involved chromosome 10, including 7 of 10 (70%) tumor stage lesions. Loss of multiple alleles was only identified in tumor stage cases, with 3 tumors undergoing allelic losses at 3 separate loci. Our results suggest that LOH studies are a robust method for evaluating genetic abnormalities in MF. Tumor stage lesions manifest increasing allelic losses compared with plaque stage. Further, in this series, several loci associated with the tumor suppressor gene PTEN on chromosome 10 appear to be associated with progression from plaque to tumor stage.
Emerson RE, Wang M, Roth LM, et al.Molecular genetic evidence supporting the neoplastic nature of the Leydig cell component of ovarian Sertoli-Leydig cell tumors.
Int J Gynecol Pathol. 2007; 26(4):368-74 [PubMed
] Related Publications
Sertoli-Leydig cell tumors (SLCT) comprise less than 1% of ovarian tumors. The nature of the Leydig cells has been a subject of controversy and it is unclear whether they are clonally related to the neoplasm or instead proliferate as a non-neoplastic response to the Sertoli-cell component. Twelve ovarian SLCT were identified and hematoxylin and eosin and unstained sections were prepared from formalin-fixed, paraffin-embedded tissue blocks. Tissue samples were microdissected from normal tissue, the Sertoli cell component, and the Leydig cell tumor component using the laser capture microdissection method. If present, tissue was also obtained from any heterologous component. Genomic DNA was extracted from the samples and polymerase chain reaction was used to amplify polymorphic sites at 5 loci: D16S402, TP53, IFNA, D17S855, and D11S1318. X-chromosome inactivation (HUMARA) analysis was also performed. LOH and/or nonrandom X-chromosome inactivation was observed in at least 1 of the 6 amplified loci in the Leydig cell component of 10 of the 12 tumors. LOH and nonrandom X-chromosome inactivation patterns of the Sertoli cell component and Leydig cell component were compared. Concordant allelic loss and/or matching X-chromosome inactivation patterns were observed in 8 (67%) of the 12 tumors. In 7 of these tumors similar LOH or X-chromosome inactivation was observed at 1 site. In 1 tumor similar LOH and/or X-chromosome inactivation was observed at 2 sites. Three tumors had heterologous components. The heterologous components similarly shared LOH/X-chromosome inactivation with the Sertoli cell components at 1 site in 1 case and 2 sites in 2 cases. These data suggest that, at least in some cases, the Leydig cell component of SLCT is neoplastic rather than reactive in nature, and shares a common clonal origin with the coexisting Sertoli cell component. Similarly, the heterologous components, when present, appear to share clonal origin with the Sertoli cell components.
Bahrami S, Cheng L, Wang M, et al.Clonal relationships between epidermotropic metastatic melanomas and their primary lesions: a loss of heterozygosity and X-chromosome inactivation-based analysis.
Mod Pathol. 2007; 20(8):821-7 [PubMed
] Related Publications
Loss of heterozygosity (LOH) has previously been demonstrated at multiple chromosome microsatellites in primary and metastatic melanomas. Epidermotropic metastases of melanoma are unique in their varied histopathologic appearance, which can mimic a primary lesion. Our objective was to compare LOH profiles in primary and epidermotropic metastatic melanoma to delineate their clonal relationship. We examined the pattern of allelic loss in the primary melanomas of nine patients in addition to the 21 corresponding epidermotropic metastatic melanomas (average 2.3 metastases per patient). DNA samples were prepared from formalin-fixed, paraffin-embedded tissue sections using laser capture microdissection. Eight DNA microsatellite markers on six different chromosomes were analyzed: D1S214 (1p), D6S305 (6q), D9S171 (9p), D9S157 (9p), IFNA (9p), D10S212 (10q), D11S258 (11q), D18S70 (18q). In addition, X-chromosome inactivation analysis was performed in tumors from four women. LOH was seen in 67% (6/9) of primary melanomas and 81% (17/21) of epidermotropic metastatic melanomas. The most frequent allelic losses in informative cases occurred at 10q (33%), 9p (22%), and 11q (22%) in primary melanomas, and at 10q (50%), 1p (44%), and 6q (39%) in epidermotropic metastatic melanomas. Primary lesions demonstrating LOH had concordant allelic loss in at least one locus in a corresponding epidermotropic metastatic melanoma in 83% (5/6) of cases. X-chromosome analysis showed nonrandom inactivation in 75% (3/4) and 71% (5/7) of primary melanoma and epidermotropic metastatic melanoma cases, respectively. Our LOH and X-chromosome inactivation analysis data suggest that epidermotropically metastatic melanomas are clonally related to their primary lesion in many cases. Our data also indicated that some cases diagnosed as epidermotropic metastatic melanoma might be divergent clones or new primaries rather than metastatic disease.
Indsto JO, Kumar S, Wang L, et al.Low prevalence of RAS-RAF-activating mutations in Spitz melanocytic nevi compared with other melanocytic lesions.
J Cutan Pathol. 2007; 34(6):448-55 [PubMed
] Related Publications
Melanocytic lesions, including Spitz nevi (SN), common benign nevi (CBN) and cutaneous metastatic melanoma (CMM), were analyzed for activating mutations in NRAS, HRAS and BRAF oncogenes, which induce cellular proliferation via the MAP kinase pathway. One of 22 (4.5%) SN tested showed an HRAS G61L mutation. Another lesion, a 'halo' SN, showed a BRAF V600E (T1796A) mutation. BRAF V600E mutations were found in two thirds (20/31) of CBN, while a further 19% (6/31) showed NRAS codon 61 mutations. One third of CMM (10/30) had various BRAF mutations of codon 600, and a further 6% (2/31) showed NRAS codon 61 mutations. Seventeen SN tested for loss of heterozygosity (LOH) at 9p and 10q regions, known to be frequently deleted in melanoma, showed LOH at the 9p loci D9S942 and IFNA. A further lesion was found with low-level microsatellite instability at one locus, D10S214. The low rate of RAS-RAF mutations (2/22, 9.1%) observed in SN suggests that these lesions harbor as yet undetected activating mutations in other components of the RAS-RAF-MEK-ERK-MAPK pathway. Germline DNA from members of 111 multiple-case melanoma families, representing a range of known (CDKN2A) and unknown predisposing gene defects, was analyzed for germline BRAF mutations, but none was found.
Jones TD, Wang M, Sung MT, et al.Clonal origin of metastatic testicular teratomas.
Clin Cancer Res. 2006; 12(18):5377-83 [PubMed
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PURPOSE: Testicular teratomas in adult patients are histologically diverse tumors that frequently coexist with other germ cell tumor (GCT) components. These mixed GCTs often metastasize to retroperitoneal lymph nodes where multiple GCT elements are frequently present in the same metastatic lesion. Neither the genetic relationships among the different components in metastatic lesions nor the relationships between primary and metastatic GCT components have been elucidated.
EXPERIMENTAL DESIGN: We examined metastases from 31 patients who underwent primary retroperitoneal lymph node dissection for metastatic testicular GCT. All patients had metastatic mature teratoma with one or more other GCT components. This study included a total of 72 metastatic GCT components and 16 primary GCT components from 31 patients. Genomic DNA samples from each component were prepared from formalin-fixed, paraffin-embedded tissue sections using laser-assisted microdissection. Loss of heterozygosity (LOH) assays for seven microsatellite polymorphic markers on chromosomes 1p36 (D1S1646), 9p21 (D9S171 and IFNA), 9q21 (D9S303), 13q22-q31 (D13S317), 18q22 (D18S543), and 18q21 (D18S60) were done to assess clonality.
RESULTS: Twenty-nine of 31 (94%) cases showed allelic loss in one or more components of the metastatic GCTs. Twenty-nine of 31 mature teratomas showed allelic loss in at least one of seven microsatellite polymorphic markers analyzed. The frequency of allelic loss in informative cases of metastatic mature teratoma was 27% (8 of 30) with D1S1646, 34% (10 of 29) with D9S171, 37% (10 of 27) with IFNA, 27% (8 of 30) with D9S303, 46% (13 of 28) with D13S317, 26% (7 of 27) with D18S543, and 36% (10 of 28) with D18S60. Completely concordant allelic loss patterns between the mature teratoma and all of the other metastatic GCT components were seen in 26 of 29 cases in which the mature teratoma component showed LOH. Nearly identical allelic loss patterns were seen in the three remaining cases. In six cases analyzed, LOH patterns of each metastatic component were compared with each GCT component of the primary testicular tumor. In all six cases, each primary and metastatic component showed an identical pattern of allelic loss.
CONCLUSION: Our data support the common clonal origin of metastatic mature teratomas with other components of metastatic testicular GCTs and with each component of the primary tumor.
Sung MT, Eble JN, Wang M, et al.Inverted papilloma of the urinary bladder: a molecular genetic appraisal.
Mod Pathol. 2006; 19(10):1289-94 [PubMed
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Inverted papilloma of urinary bladder is an uncommon urothelial neoplasm. Its relationship to urothelial carcinoma is controversial. Little is known of the genetic abnormalities of inverted papilloma. To better understand its genetics, we analyzed 39 inverted papillomas, including 36 from men and three from women, for loss of heterozygosity (LOH). We examined four polymorphic microsatellite markers located on chromosome 9q32-33(D9S177), chromosome 9p22 (IFNA), chromosome 3p14.2 (D3S1300) and chromosome 17p13.1 (TP53), where genetic alterations occur frequently in urothelial carcinomas. Additionally, the status of inactivation of X-chromosome was examined in three female patients. The frequency of LOH in informative cases was 8% (3 of 37) for D9S177, 10% (4 of 38) for TP53, 8% (3 of 37) for IFNA and 8% (3 of 36) for D3S1300. In the analysis of X-chromosome inactivation, all three cases yielded informative results and one had nonrandom inactivation of X-chromosomes. The monoclonal origin demonstrated in the study of X-chromosome inactivation indicates the clonal process of inverted papilloma; however, the low incidence of LOH supports the view that inverted papilloma in urinary bladder is a benign neoplasm with molecular genetic abnormalities different from those of urothelial carcinoma.
Jones TD, Wang M, Eble JN, et al.Molecular evidence supporting field effect in urothelial carcinogenesis.
Clin Cancer Res. 2005; 11(18):6512-9 [PubMed
] Related Publications
PURPOSE: Human urothelial carcinoma is thought to arise from a field change that affects the entire urothelium. Multifocality of urothelial carcinoma is a common finding at endoscopy and surgery. Whether these coexisting tumors arise independently or are derived from the same tumor clone is uncertain. Molecular analysis of microsatellite alterations and X-chromosome inactivation status in the cells from each coexisting tumor may further our understanding of urothelial carcinogenesis.
EXPERIMENTAL DESIGN: We examined 58 tumors from 21 patients who underwent surgical excision for urothelial carcinoma. All patients had multiple separate foci of urothelial carcinoma (two to four) within the urinary tract. Genomic DNA samples were prepared from formalin-fixed, paraffin-embedded tissue sections using laser-capture microdissection. Loss of heterozygosity (LOH) assays for three microsatellite polymorphic markers on chromosome 9p21 (IFNA and D9S171), regions of putative tumor suppressor gene p16, and on chromosome 17p13 (TP53), the p53 tumor suppressor gene locus, were done. X-chromosome inactivation analysis was done on the urothelial tumors from 11 female patients.
RESULTS: Seventeen of 21 (81%) cases showed allelic loss in one or more of the urothelial tumors in at least one of the three polymorphic markers analyzed. Concordant allelic loss patterns between each coexisting urothelial tumor were seen in only 3 of 21 (14%) cases. A concordant pattern of nonrandom X-chromosome inactivation in the multiple coexisting urothelial tumors was seen in only 3 of 11 female patients; of these 3 cases, only one displayed an identical allelic loss pattern in all of the tumors on LOH analysis.
CONCLUSION: LOH and X-chromosome inactivation assays show that the coexisting tumors in many cases of multifocal urothelial carcinoma have a unique clonal origin and arise from independently transformed progenitor urothelial cells, supporting the "field effect" theory for urothelial carcinogenesis.
In most cases, small-cell carcinoma of the urinary bladder is admixed with other histological types of bladder carcinoma. To understand the pathogenetic relationship between the two tumor types, we analyzed histologically distinct tumor cell populations from the same patient for loss of heterozygosity (LOH) and X chromosome inactivation (in female patients). We examined five polymorphic microsatellite markers located on chromosome 3p25-26 (D3S3050), chromosome 9p21 (IFNA and D9S171), chromosome 9q32-33 (D9S177), and chromosome 17p13 (TP53) in 20 patients with small-cell carcinoma of the urinary bladder and concurrent urothelial carcinoma. DNA samples were prepared from formalin-fixed, paraffin-embedded tissue sections using laser-assisted microdissection. A nearly identical pattern of allelic loss was observed in the two tumor types in all cases, with an overall frequency of allelic loss of 90% (18 of 20 cases). Three patients showed different allelic loss patterns in the two tumor types at a single locus; however, the LOH patterns at the remaining loci were identical. Similarly, the same pattern of nonrandom X chromosome inactivation was present in both carcinoma components in the four cases analyzed. Concordant genetic alterations and X chromosome inactivation between small-cell carcinoma and coexisting urothelial carcinoma suggest that both tumor components originate from the same cells in the urothelium.
Beaty MW, Quezado M, Sobel ME, et al.Loss of heterozygosity on chromosome 1 and 9 and hormone receptor analysis of metastatic malignant melanoma presenting in breast.
Int J Surg Pathol. 2005; 13(1):9-18 [PubMed
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Malignant melanoma (MM), the most common metastatic solid tumor to involve the breast, may present as a diagnostic problem, frequently requiring the use of ancillary studies for accurate diagnosis. The implication of hormonal interplay is strong since metastatic MM to the breast is seen nearly always in women. However, the role of hormonal status as a predisposing factor in the development of this entity is largely unresolved. A number of chromosomal loci, including 1p36 and 9p21-22, appear to harbor critical genes important to melanoma tumorigenesis, and additionally chromosome 9q22.3-31. We wanted to know if metastatic MM in breast showed chromosome 1p and 9p genetic alterations (loss of heterozygosity) similar to those that occur in primary cutaneous MM, and whether additional 9q LOH changes are present. Hormonal receptor status of the metastatic MM was also determined. We identified 20 patients with known MM metastatic to the breast, which we analyzed with the following genetic markers: D9S12 (9q22.3), D9S171 (9p21), IFNA (9p22), and D1S450 (1p). Visually directed microdissection was performed on archival histologic slides containing both tumor and adjacent normal breast epithelium, followed by single-step DNA extraction and polymerase chain reaction (PCR) amplification for evaluation of loss of heterozygosity (LOH) for the above-listed markers. Immunohistochemical (IHC) stains for estrogen receptor (ER) and progesterone receptor (PR) was performed on 10 of the cases. Twelve of the 20 cases contained DNA suitable for PCR amplification following direct visualization microdissection. Four of 8 (50%) informative cases showed LOH at 9p21 with D9S171. Ten cases were heterozygous for IFNA, with 2 cases (20%) showing LOH at this locus. These particular cases also showed LOH at 9p21. One of 9 (11%) informative cases showed LOH for D1S450 (1p36). Five cases were heterozygous for D9S12, and 2 (40%) showed LOH in the tumor at 9q22.3. IHC stains for ER and PR were negative in the 10 tumors studied. Metastatic MM presenting as a breast mass is an interesting entity often requiring IHC studies for diagnosis, particularly when the histologic features simulate breast carcinoma or when no primary tumor is known. These tumors are ER and PR negative. Metastatic MM involving the breast shows similar genetic allelic losses on chromosome 9p21-22 (50%) and 1p36 (11%), as previously described in primary cutaneous MM. Additional LOH was observed at the 9q22.3-31 locus (40%). We suggest this locus to be investigated for harboring potential genes important in the tumorigenesis of cutaneous MM.
Xu XF, Gao YN, Cheng SJDetailed deletion mapping of loss of heterozygosity on 9p13-23 in laryngeal squamous cell carcinoma by microsatellite analysis.
Chin Med J (Engl). 2004; 117(8):1204-9 [PubMed
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BACKGROUND: This study was designed to investigate the hot spots of microsatellite loss of heterozygosity (LOH) on 9p13-23 in laryngeal squamous cell carcinoma and to find out the correlation between the incidence of microsatellite LOH and the clinicopathological parameters.
METHODS: Tumor tissues were obtained from paraffin embedded sections with microdissection. Genomic DNA was extracted from tumor tissues and peripheral blood lymphocytes with the phenol-chloroform. Polymerase chain reaction (PCR) amplification and denaturing gel electrophoresis were carried out in a set of 42 squamous cell carcinoma (SCC) of larynx and corresponding peripheral blood lymphocytes using 13 highly polymorphic microsatellite markers on 9p13-23. The correlation was analyzed between microsatellite LOH at the high frequency on 9p13-23 and clinicopathological parameters in the patients with squamous cell carcinoma of larynx.
RESULTS: Of the 42 laryngeal cancers, 41 (97.6%) showed LOH in at least one of the microsatellite markers tested on 9p13-23. The most frequently deleted marker was D9S162 in 17 of the 19 (89.5%) informative samples. The marker D9S171, which is located on 9p21, had LOH detected in 12 of the 15 informative cases (80.0%). LOH at the D9S1748 marker (closest to the p16 gene locus) was detected in 18 of the 36 informative cases (50.0%). Allelic deletion mapping revealed two minimal regions of LOH encompassing markers D9S161-D9S171 on 9p21 and IFNA-D9S162 on 9p22-23. Multiple LOH (> or = 4) on 9p21-23 was found more frequently in the patients under 60 years, with supraglottic SCC or cervical lymph node metastasis than those over 60 years, with glottic SCC or without cervical lymph node metastasis (P < 0.01 or 0.01, 0.05, respectively). On the contrary, there was no correlation between T stages or pathologic classification and the frequency of LOH on 9p21-23 in 42 SCC of Larynx.
CONCLUSIONS: These findings imply the presence of at least two putative tumor suppressor genes on 9p13-23 in laryngeal SCC. Multiple genetic alterations are probably implicated in supraglottic SCC with cervical lymph node metastasis in younger patients.
Lubyova B, Kellum MJ, Frisancho AJ, Pitha PMKaposi's sarcoma-associated herpesvirus-encoded vIRF-3 stimulates the transcriptional activity of cellular IRF-3 and IRF-7.
J Biol Chem. 2004; 279(9):7643-54 [PubMed
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Kaposi's sarcoma-associated herpesvirus has been linked to Kaposi's sarcoma, body cavity-based lymphoma, and Castleman's disease. The Kaposi's sarcoma-associated herpesvirus genome contains a cluster of open reading frames encoding proteins (vIRFs) with homology to the cellular transcription factors of the interferon regulatory factor family. vIRF-3, also called LANA2, is a latently expressed nuclear protein. Here we demonstrate that vIRF-3 directly interacts with cellular interferon regulatory factor (IRF) IRF-3, IRF-7, and the transcriptional co-activator CBP/p300. The mapping of the vIRF-3 binding domain revealed that vIRF-3 associates with both IRF-3 and IRF-7 through its C-terminal region. The p300 domain, which interacts with vIRF-3, is distinct from the previously identified IBiD domain, to which both vIRF-1 and IRF-3 bind. Thus, in contrast to vIRF-1, vIRF-3 neither blocks the interaction between IRF-3 and p300 nor inhibits the histone acetylation. Although vIRF-3 is not a DNA-binding protein, it is recruited to the IFNA promoters via its interaction with IRF-3 and IRF-7. The presence of vIRF-3 in the enhanceosome assembled on the IFNA promoters increases binding of IRF-3, IRF-7, and acetylated histone H3 to this promoter region. Consequently, vIRF-3 stimulates the IRF-3- and IRF-7-mediated activation of type I interferon (IFNA and IFNB) genes and the synthesis of biologically active type I interferons in infected B cells. These studies illustrate that vIRF-3 and vIRF-1 have clearly distinct functions. In addition to its co-repressor activity, vIRF-3 can also act as a transcriptional activator on genes controlled by cellular IRF-3 and IRF-7.
Levanat S, Situm M, Crnić I, et al.Alterations in CDKN2A locus as potential indicator of melanoma predisposition in relatives of non-familial melanoma cases.
Croat Med J. 2003; 44(4):418-24 [PubMed
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AIM: To examine constitutional alterations of CDKN2A/p16INK4A locus as a potential indicator of melanoma predisposition among the first-degree relatives of patients with malignant melanoma.
METHOD: The study included eight families with a single member affected with melanoma. Members of the families were screened for allelic cosegregation with 9p21 region polymorphic markers IFNA, D9S126, and D9S104. The patient's tumors were screened for loss of heterozygosity (LOH) with the same markers, as well as for single strand conformational polymorphism (SSCP) variability of CDKN2A. In suspect cases, constitutional DNA was examined by SSCP and direct sequencing.
RESULTS: LOH was detected in four cases, and SSCP indicated variability in at least one CDKN2A exon in these tumor samples. In three of four LOH cases, the remaining allele cosegregated within the family, which was interpreted as a preliminary indicator of potential genetic predisposition. In one of these three families, we found constitutional CDKN2A mutations in the patient and one of the relatives. In the second family, only the patient had the constitutionally altered gene, whereas no constitutional CDKN2A alterations were detected in the third family. All significant mutations were different and had not been reported before.
CONCLUSION: We detected one case of melanoma predisposition among unaffected family members, which corresponded to statistical expectations for such a small number of screened families. Since constitutional mutations of CDKN2A exons have limited incidence, our stepwise approach seemed to be more informative and more affordable than straightforward CDKN2A sequencing of all subjects.
Park S, Kim SW, Kim SH, et al.Loss of heterozygosity in ampulla of Vater neoplasms during adenoma-carcinoma sequence.
Anticancer Res. 2003 May-Jun; 23(3C):2955-9 [PubMed
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BACKGROUND: Ampulla of Vater cancers arise from precancerous lesions and existence of an adenoma-carcinoma sequence is based on morphological observations.
MATERIALS AND METHODS: We studied the loss of heterozygosity (LOH) in 22 adenomas, 32 carcinomas and 10 metastatic lesions using nine dinucleotide-repeated sequences in 3p, 8p, 8q, 9p, 10q, 13q, 17p, 17q, 18q.
RESULT: High LOH frequencies (> 50%) of 9p (IFNA) and 17p (TP53) were observed in adenomas and carcinomas. The frequency of LOH is higher in adenoma (55.6%) than in carcinoma (40%) for 8p (D8S261), but it is the same in cases having adenoma (57.1%) and carcinoma (57.1%) in the same lesion. LOH for 13q (D13S118), 17q (D17S520) and for 18q (D18S34) were more common in carcinomas than in adenomas, but statistically a significant difference was observed only on 13q (p < 0.05). Fractional allelic loss (FAL) is not correlated with any of the clinicopathological parameters.
CONCLUSION: Tumor suppressor genes located in the 8p, 9p and 17p chromosomes might be associated with the early stage of tumorigenesis and that in 13q is involved during the adenoma-carcinoma progression.
Ovarian clear cell carcinoma (OCCC) accounts for a small but significant proportion of all ovarian cancers and is a distinct clinical and pathological entity. It tends to be associated with poorer response rates to chemotherapy and with a worse prognosis. Little is known about possible underlying genetic changes. DNA extracted from paraffin-embedded samples of 18 pure OCCC cases was analysed for genetic imbalances using comparative genomic hybridisation (CGH). All of the 18 cases showed genomic alterations. The mean number of alterations detected by CGH was 6 (range 1-15) indicating a moderate level of genetic instability. Chromosome deletions were more common than amplifications. The most prominent change involved chromosome 9 deletions in 10 cases (55%). This correlates with changes seen in other epithelial ovarian cancers. This deletion was confirmed using microsatellite markers to assess loss of heterozygosity (LOH) at four separate loci on chromosome 9. The most distinct region of loss detected was around the IFNA marker at 9p21 with 41% (11 out of 27 cases) LOH. Other frequent deletions involved 1p (five out of 18; 28%); 11q (four out of 18; 22%) and 16 (five out of 18; 28%). Amplification was most common at chromosome 3 (six out of 18; 33%); 13q (four out of 18; 22%) and 15 (three out of 18; 17%). No high-level amplifications were identified. These features may serve as useful prognostic indicators in the management of OCCC.
Bogdan I, Smolle J, Kerl H, et al.Melanoma ex naevo: a study of the associated naevus.
Melanoma Res. 2003; 13(2):213-7 [PubMed
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It has been shown that the co-occurrence of melanoma and pre-existing naevus is not a random event and that acquired naevi may be precursors of melanoma. A critical area of chromosomal loss at 9p21 has been implicated in the genesis of malignant melanoma, representing a site of frequent somatic chromosomal deletions in melanoma. Allelic deletions within this chromosomal region most often include the tumour suppressor gene p16. The objective of this study was to search for allelic deletions on chromosome 9p21 in naevus cell clusters. A microdissection-based approach was used to analyse 30 archived primary cutaneous melanomas and associated naevi for loss of heterozygosity (LOH) at 9p21 using the polymorphic DNA markers D9S171 and IFNA. LOH was detected in 10 out of 27 informative naevi (37%) at D9S171 and in eight out of 19 (42%) at IFNA in the dissected naevus cell clusters, and in nine out of 27 (33%) at D9S171 and seven out of 19 (36%) at IFNA in the associated melanomas. In eight out of 46 (17%) cases, LOH was detected simultaneously in the naevus and the associated melanoma using both markers. Our results suggest a causal relationship for the development of melanoma within a pre-existent associated naevus. These data support the hypothesis that lesions within 9p21 play an important role in early melanoma development, since these genetic alterations are found in histologically benign melanoma-associated naevi.
An Q, Liu Y, Gao Y, et al.Deletion of tumor suppressor genes in Chinese non-small cell lung cancer.
Cancer Lett. 2002; 184(2):189-95 [PubMed
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In the present study, we used 22 microsatellite markers flanking to or within 13 known or candidate tumor suppressor genes (TSGs) to detect loss of heterozygosity (LOH) in these chromosomal regions among 41 cases of non-small cell lung cancer, including 28 squamous cell carcinoma (SCC) and 13 adenocarcinoma (ADC). The studied TSGs comprised FHIT, VHL, APC, PRLTS, p16, IFNA, PTEN, p57, ATM, p53, BRCA1, DPC4 and DCC. Our data demonstrated frequent allelic losses of FHIT, p53, IFNA, VHL and p16 in both SCC and ADC. PTEN and ATM showed the least frequency of LOH, while no deletion of BRCA1 was detected in all tumor samples. LOH analysis of PRLTS was extended to 26 cases of ADC, which demonstrated significantly higher frequency of LOH than SCC. Our data indicated a possible correlation between specific TSG(s) and either histological type of lung cancer, and more attention should be paid to the PRLTS gene, which might play an important role in the development of ADC.
Wang C, Lu X, Liu G, et al.Detailed deletion mapping on chromosome region 9p21 in human periampullary neoplasms.
Chin Med J (Engl). 2001; 114(6):588-91 [PubMed
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OBJECTIVE: To further define the extent of chromosome 9p21 deletion in periampullary neoplasms.
METHODS: The loss of heterozygosity at 5 microsatellite polymorphic markers on chromosome 9p21 was detected by polymerase chain reaction (PCR), polyacrylamide gel electrophoresis (PAGE) and silver staining in 35 specimens of periampullary neoplasms and their matching blood samples.
RESULTS: Fifty percent (4/8) of pancreatic cancer cases showed the loss of heterozygosity at one or more microsatellite loci, with the more frequent sites of D9S974 (37.5%) and D9S942 (28.6%), and some showing consecutive allelic loss. Sixty-two point five percent (5/8) of ampullary carcinoma cases showed loss of heterozygosity at one or more of the loci, frequent site of loss being D9S942 (42.9%) and the next most frequent being IFNA (37.5%) and D9S171 (37.5%). Loss of one locus was observed in 14.2% (1/7) of insulinoma.
CONCLUSION: The minimal common region of chromosome deletion in periampullary neoplasms is defined between the D9S974 and D9S942 loci within a 15 kb interval in 9p21, suggesting the involvement of a novel tumor suppressor gene in their carcinogenesis.
Cheng L, Bostwick DG, Li G, et al.Conserved genetic findings in metastatic bladder cancer: a possible utility of allelic loss of chromosomes 9p21 and 17p13 in diagnosis.
Arch Pathol Lab Med. 2001; 125(9):1197-9 [PubMed
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CONTEXT: Molecular analysis of microsatellite alterations of biologically distinct tumor cell subpopulations from the same patient may aid in the determination of tumor origin and further our understanding of the genetic basis of cancer progression.
DESIGN: The authors examined the pattern of allelic loss with polymorphic microsatellite markers on chromosome 9p21 (D9S161, D9S171, IFNA), regions of putative tumor suppressor gene p16, and on chromosome 17p13 (TP53), the p53 locus, in matched primary and metastatic bladder cancers from 9 patients. All patients underwent cystectomy for bladder cancer and had regional lymph node metastases at the time of surgery. Genomic DNA was prepared from primary cancers and matched synchronous lymph node metastases using a microdissection method.
RESULTS: The overall frequency of allelic loss was 78% in primary cancer and 89% in paired metastatic cancer. The frequency of allelic loss in the primary cancer was 86% with D9S161, 67% with D9S171, 71% with IFNA, and 80% with TP53. The frequency of allelic loss in matched metastatic cancer was 100% with D9S161, 62% with D9S171, 71% with IFNA, and 80% with TP53. An identical pattern of allelic imbalance (allelic loss or retention) at multiple DNA loci was observed in matched primary and metastatic carcinoma in 8 (88%) cases. One case showed allelic loss in the metastasis, but not in the primary cancer.
CONCLUSIONS: The pattern of allelic loss at chromosome 9p21 (p16) and 17p13 (p53) was generally maintained during cancer progression to metastasis, and identical allelic loss in primary cancer was conserved in paired metastatic carcinoma. These data suggest that these genetic changes may be useful in establishing a diagnosis and determining tumor origins in difficult cases.
Grady B, Goharderakhshan R, Chang J, et al.Frequently deleted loci on chromosome 9 may harbor several tumor suppressor genes in human renal cell carcinoma.
J Urol. 2001; 166(3):1088-92 [PubMed
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PURPOSE: Loss of various loci on chromosome 9 has been reported in various cancers. To determine the frequency of deletions at different loci of chromosome 9 in renal cell carcinoma microdissected samples of normal renal epithelium and carcinoma from the same patients were analyzed.
MATERIALS AND METHODS: DNA was isolated from microdissected sections of normal and tumor cells of 60 renal specimens, amplified by polymerase chain reaction and analyzed for loss of heterozygosity on chromosome 9 using the 16 microsatellite markers D9S178, D9S157, D9S274, D9S168, D9S285, D9S156, D9S1839, D9S162, IFNA, D9S736, D9S171, D9S1749, D9S273D9S270, D9S153 and D9S170. Loss of heterozygosity was analyzed by a polymerase chain reaction based technique developed at our laboratory.
RESULTS: This study showed a high incidence of loss of heterozygosity on chromosome 9 in renal cell carcinoma. Of 60 cases 44 (73%), 24 (40%) and 14 (23%) showed loss of heterozygosity at a minimum of 1, at a minimum of 3 and at 4 or more loci, respectively. The main deletion was found on the 9p21 region at loci DS171 in 38% of cases, D9S1749 in 42% and DS270 in 14%. Overall deletion on chromosome 9p21 was noted in 57% of renal cancer cases. Other deleted regions were on chromosome 9p'0022 to 23 at loci D9S157 in 37% of cases, D9S274 in 20%, D9S168 in 27%, D9S285 in 20%, D9S156 in 12%, D9S1839 in 17% and D9S162 in 24%. Overall deletion at chromosome 9q32 to 33 was noted in 46% of renal cell carcinoma cases. Chromosome 9q32 to 33 also showed deletion at locus D9S170 in 22% of renal cell carcinoma cases. When we compared the incidence of deletion at various loci on chromosome 9 according to renal cell carcinoma grade, we found a higher rate of deletion in advanced grades of renal cell carcinoma. A candidate target tumor suppressor gene, p16 (MTS-1/CDKN2), has been identified within the 9p21 deleted region in various cancers. In our study the expression of p16 protein was absent or low in renal cell cancer samples, suggesting that loss of the p16 gene may be involved in renal cell carcinogenesis.
CONCLUSIONS: Our study demonstrates a high incidence of loss of heterozygosity on chromosome 9, mainly 9p21 and 9p22 to 23, in renal cell carcinoma, suggesting several putative tumor suppressor genes on these regions. The identification of other tumor suppressor genes on the 9p21 and 9p22 to 23 regions warrants further studies.
Bogdan I, Xin H, Burg G, Böni RHeterogeneity of allelic deletions within melanoma metastases.
Melanoma Res. 2001; 11(4):349-54 [PubMed
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During the initiation and progression of malignant melanoma, a series of different genetic events accumulate on several different chromosomes. The biological heterogeneity of tumour cells presents a major problem, preventing effective treatment of melanoma. To examine the degree of genetic heterogeneity, we searched for allelic losses (loss of heterozygosity; LOH) on chromosomes 9p, 9q, 1p and 17p, examining different areas within human melanoma metastases. All of the examined metastases were informative within at least one dissected area for at least one marker. Out of 29 areas in 11 melanoma metastases, 58% showed LOH with at least one marker. On chromosome 9p21-22, eight out of 26 informative loci (31%) showed LOH at D9S171 (three not informative), two out of 18 (11%) at IFNA (11 not informative) and seven out of 24 (29%) at D9S169 (five not informative). LOH on chromosome 9q22.3 was examined by the microsatellite marker D9S12; three out of 24 areas (12.5%) showed LOH, and five were not informative. Deletions on chromosome 1p were assessed using D1S450. Four out of 25 (16%) showed LOH; four were not informative. Deletions on chromosome 17p13 were examined with TP53; two out of 21 cases (9%) showed LOH, and eight were not informative. Our data demonstrate an impressive heterogeneity of allelic losses in the investigated chromosomal areas within the same metastatic lesion. This suggests that there is not one specific genetic alteration that accounts for melanoma progression to metastases. Rather there seem to be multiple genetic alterations accumulating even on the same chromosome, and progression from melanoma to metastases is paralleled by the accumulation of clones harbouring multiple genetic abnormalities.