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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Important risk factors for melanoma are densely clustered melanocytic nevi (common moles) and mutations in the p16 (CDKN2A) gene. Nevi may be subclassified as raised or flat. In our sample, raised nevi were 27% of the total, and the two kinds had a correlation of.33. Correlations for total-nevus count (TNC) in 153 MZ and 199 DZ twin pairs were.94 and.60, respectively, which are compatible with a very-high degree of genetic determination. We hypothesized that some of the genetic variance might be due to variation in the p16 gene. Analysis of linkage to a highly polymorphic marker (D9S942), located close to p16, detected quantitative-trait-loci (QTL) effects accounting for 27% of variance in TNC, rising to 33% if flat but not raised moles were considered. Total heritability was higher for raised (.69) than for flat (.42) moles, but QTL linkage was 0 for raised moles, whereas it accounted for 80% of the heritability of flat moles; additionally, family environment accounted for only 15% of variance in raised versus 46% in flat moles. These findings suggest that raised and flat nevi have very different etiologies. Longer alleles at D9S942 were associated with higher flat-mole counts, and a novel modification to a within-sibship association test showed that this association is genuine and not due to population stratification, although it accounts for only 1% of total variance. Since germline mutations in the exons of CDKN2A are rare, it is likely that variants in the noncoding regions of this gene, or in another gene nearby, are responsible for this major determinant of moliness and, hence, of melanoma risk.
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PMID:A major quantitative-trait locus for mole density is linked to the familial melanoma gene CDKN2A: a maximum-likelihood combined linkage and association analysis in twins and their sibs. 1041 91

The etiology of malignant melanoma has been intensely studied over the last decade. Much of the recent work focuses on oncongenes and tumour suppressor genes and the role of apoptosis in melanoma. Loss of tumour suppressor proteins such as p16 has been documented in melanoma and correlates with tumour progression. Mutations in the tumour suppressor p53 have also been documented in melanoma. The proto-oncongene Bcl-2 encodes a protein that inhibits apoptosis. Bcl-2 is found in normal melanocytes and benign nevi. However, lower levels are seen in melanoma. To investigate the relationship between melanoma and nevi, in our Basic and Clinical Science section, Dr. Radhi examines the expression of p53, p16, and Bcl in malignant melanoma arriving in benign nevi. P53 immunoreactivity was found only in the malignant component, with no expression being seen in the benign components of the lesion. This suggests that this tumour suppressor gene is involved in the pathogenesis of melanoma.
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PMID:The etiology of malignant melanoma. 1057 55

Patients with familial malignant melanoma(FMM) are susceptible for melanoma and multiple dysplastic nevi(atypical mole). FMM is also called as dysplastic nevus syndrome or familial atypical mole and melanoma syndrome. The number of Japanese patients with FMM is very low. In 1994, p16(MTS1, INK4A, CDK4I, CDKN2) gene was cloned as the gene for FMM. p16 gene locus also codes for p14ARF and acts as tumor suppressor through activation of Rb by p16 and p53 by p14ARF. Approximately 20% of FMM patients were shown to carry the germline mutations of p16, indicating the presence of another gene or other genes for FMM, which also may be involved in the development of sporadic malignant melanoma.
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PMID:[Familial malignant melanoma]. 1092 9

Familial atypical multiple mole melanoma (FAMMM) is an autosomal dominant disease characterized by the familial occurrence of malignant melanoma of the skin and multiple atypical precursor lesions. Germline mutations in the p16 (CDKN2A) gene have been reported in at least a quarter of such families. An association has been reported between p16 mutations and pancreatic cancer. The aim of this study was to assess the risk of developing pancreatic and other cancers in Dutch FAMMM families with a 19 bp deletion in exon 2 of the p16 gene (p16-Leiden). Mutation analysis was performed in 27 families suspected of FAMMM. Clinical and pathological data were collected from all relatives affected with cancer. A p16-Leiden mutation was identified in 19 families. These families included 86 patients with melanoma. The second most frequent cancer was pancreatic cancer, which was observed in 15 patients from 7 families. The mean age at diagnosis of pancreatic cancer was 58 years (range 38-77 years). The estimated cumulative risk of developing pancreatic cancer in putative mutation carriers by age 75 years was 17%. In 8 p16-Leiden-negative families, no cases of pancreatic cancer occurred. p16 mutation carriers have a considerable risk of developing pancreatic cancer. Further studies should evaluate the value of surveillance of the pancreas in these high-risk families.
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PMID:Risk of developing pancreatic cancer in families with familial atypical multiple mole melanoma associated with a specific 19 deletion of p16 (p16-Leiden). 1095 90

Approximately 10% of human cutaneous melanoma cases occur in families with the familial atypical multiple mole melanoma (FAMMM) syndrome, which is characterised by the familial occurrence of melanomas and atypical precursor naevi. A melanoma-associated gene has been mapped to 9p2l, encoding for the tumour suppressor gene CDKN2A. Worldwide, germline mutations in melanoma kindreds implicate this cell cycle regulator (p16) as a susceptibility gene for malignant melanoma. Most FAMMM families registered at the Leiden Pigmented Lesions Clinic share the same CDKN2A inactivating deletion (P16-Leiden). Presymptomatic DNA diagnosis will now be available for P16-Leiden positive FAMMM family members at the Leiden University Medical Centre.
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PMID:[From gene to disease; from p16 to melanoma]. 1110 70

Approximately 5% to 10% of patients with pancreatic cancer have one or more first-degree relatives with this disease. A subset of these individuals have a hereditary form of pancreatic cancer designated by association with such hereditary disorders as familial adenomatous polyposis, hereditary nonpolyposis colorectal cancer, hereditary pancreatitis, or familial atypical multiple mole melanoma (FAMMM) syndrome. A subset of those FAMMM kindred with the CDKN2A (p16) germline mutation that expresses both pancreatic cancer and malignant melanoma may constitute a new hereditary pancreatic cancer-prone syndrome.
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PMID:Update on familial pancreatic cancer. 1127 79

Syringocystadenoma papilliferum (SP) is a benign tumor most commonly located on the scalp or face, which frequently arises from a nevus sebaceus (NS). Transition of SP to basal cell carcinoma (BCC) and, albeit rarely, to metastatic adenocarcinoma may occur. Allelic deletions of the human homologue of the drosophila patched gene (PTCH) occur in both NS and BCC. To search for genetic changes in SP, a microdissection-based genetic analysis using polymorphic markers at 9q22 (PTCH; D9S15, D9S303, D9S287, D9S252) as well as markers at 9p21 flanking the tumor suppressor gene p16 (IFNA, D9S171) was performed. Glandular epithelium consisting of two rows of cells as well as adjacent normal tissue or inflammatory infiltrates in the stroma, when present, was dissected and subjected to single-step DNA extraction and loss of heterozygosity (LOH) analysis. Two of 10 informative SP cases showed LOH at 9q22 (PTCH). Three of 7 informative SP cases showed allelic deletions at 9p21 (p16). Allelic loss at 9q22 is consistent with the clinical observation of transition of SP to BCC. The finding of frequent allelic loss at 9p21 is unlikely to be related to the rare transition of SP to metastatic adenocarcinoma. Our study supports the hypothesis of a gatekeeper role of the tumor suppressor gene p16 in a variety of benign and malignant tumors, including SP.
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PMID:Syringocystadenoma papilliferum: a study of potential tumor suppressor genes. 1128 1

The biological significance of melanocytic lesions depends on its association with melanomas. Some melanocytic lesions are considered as precursors of melanoma while others may share histological similarities with malignant lesions. Melanomas exhibit clinical, epidemiological and histological heterogeneity. Molecular and cytogenetic studies may supply additional information to supplement the histopathological evaluation. Several genes have been linked to melanomas: CMM1 on chromosome 1p36 and CMM2 on 9p21, and other chromosomal regions where tumor suppressor genes are located as p16 (9p21) and p53 (17p13). We analyzed different melanocytic lesions to determine LOH at 9p21 and 17p13 and to assess clonality by the HUMARA technique. All the malignant melanomas were monoclonal and all the benignant lesions we analyzed were policlonal in our series including deep penetrating nevi and Spitz Nevi. LOH at 9p21 was determined in 60% melanomas, 50% Spitz and 0% intradermal nevi. In conclusion, genotypic changes may supplement the phenotypic or morphological evaluation of melanocytic lesions.
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PMID:[Genetic alterations in the differential diagnosis of melanocytic diseases]. 1138 55

Germline mutations of the cell-cycle regulator p16 (also called "CDKN2A") in kindreds with melanoma implicate this gene in susceptibility to malignant melanoma. Most families with familial atypical multiple-mole melanoma (FAMMM) who are registered at the Leiden dermatology clinic share the same p16-inactivating deletion (p16-Leiden). Incomplete penetrance and variable clinical expression suggest risk modification by other genetic and/or environmental factors. Variants of the melanocortin-1 receptor (MC1R) gene have been shown to be associated with red hair, fair skin, and melanoma in humans. Carriers of the p16-Leiden deletion in Dutch families with FAMMM show an increased risk of melanoma when they also carry MC1R variant alleles. The R151C variant is overrepresented in patients with melanoma who are from families with the p16-Leiden mutation. Although some of the effect of the R151C variant on melanoma risk may be attributable to its effect on skin type, our analyses indicate that the R151C variant contributes an increased melanoma risk even after statistical correction for its effect on skin type. These findings suggest that the R151C variant may be involved in melanoma tumorigenesis in a dual manner, both as a determinant of fair skin and as a component in an independent additional pathway.
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PMID:Melanocortin-1 receptor variant R151C modifies melanoma risk in Dutch families with melanoma. 1150 Aug 6

The helix-loop-helix transcription factor Id1 coordinates cell growth and differentiation pathways within mammalian cells and has been implicated in regulating G(1)-S phase cell cycle transitions. Recently Id1 has been shown to repress Ets- and E-protein-mediated transactivation of p16/Ink4a. Because the p16/Ink4a protein has been demonstrated to be inactivated in subsets of familial and sporadic melanomas, we sought to determine whether Id1 regulation of p16/Ink4a expression might be involved in the development of this human tumor. Here we evaluate 21 melanocytic lesions at various stages of malignant progression from common melanocytic nevi to metastatic melanomas and examine these lesions for Id1 and p16/Ink4a expression. We demonstrate that Id1 expression correlates with loss of p16/Ink4a expression in melanoma in situ; however, more advanced stages of melanoma do not express Id1 except within perivascular regions, despite overall decreased p16/Ink4a expression in these lesions. Microdissected lesions were evaluated for p16/Ink4a sequence, and invasive melanomas that did not express Id1 were found to have sustained inactivating p16/ink4a mutations. These data suggest a role for Id1 in regulating p16/Ink4a expression in early melanomas and demonstrate that later genetic changes may provide for irreversible loss of p16 expression in advanced stages of this tumor.
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PMID:The transcriptional repressor of p16/Ink4a, Id1, is up-regulated in early melanomas. 1150 43


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