Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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

Risk factors for melanoma include environmental (particularly ultraviolet exposure) and genetic factors. In rare families, susceptibility to melanoma is determined by high penetrance mutations in the genes CDKN2A or CDK4, with more common, less penetrant genes also postulated. A further, potent risk factor for melanoma is the presence of large numbers of melanocytic nevi so that genes controlling nevus phenotype could be such melanoma susceptibility genes. A large Australian study involving twins aged 12 y of predominantly U.K. ancestry showed strong evidence for genetic influence on nevus number and density. We carried out essentially the same study in the U.K. to gain insight into gene-environment interactions for nevi. One hundred and three monozygous (MZ) and 118 dizygous (DZ) twin pairs aged 10-18 y were examined in Yorkshire and Surrey, U.K. Nevus counts were, on average, higher in boys (mean = 98.6) than girls (83.8) (p = 0.009) and higher in Australia (110.4) than in the U.K. (79.2, adjusted to age 12 y, p < 0.0001), and nevus densities were higher on sun-exposed sites (92 per m2) than sun-protected sites (58 per m2) (p < 0.0001). Correlations in sex and age adjusted nevus density were higher in MZ pairs (0.94, 95%CI 0.92-0.96) than in DZ pairs (0.61, 95%CI 0.49-0.72), were notably similar to those of the Australian study (MZ = 0.94, DZ = 0.60), and were consistent with high heritability (65% in the U.K., 68% in Australia). We conclude that emergence of nevi in adolescents is under strong genetic control, whereas environmental exposures affect the mean number of nevi.
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PMID:Heritability and gene-environment interactions for melanocytic nevus density examined in a U.K. adolescent twin study. 1151 14

The incidence of melanoma increases markedly in the second decade of life but almost nothing is known of the causes of melanoma in this age group. We report on the first population-based case-control study of risk factors for melanoma in adolescents (15-19 years). Data were collected through personal interviews with cases, controls and parents. A single examiner conducted full-body nevus counts and blood samples were collected from cases for analysis of the CDKN2A melanoma predisposition gene. A total of 201 (80%) of the 250 adolescents with melanoma diagnosed between 1987 and 1994 and registered with the Queensland Cancer Registry and 205 (79%) of 258 age-, gender- and location-matched controls who were contacted agreed to participate. The strongest risk factor associated with melanoma in adolescents in a multivariate model was the presence of more than 100 nevi 2 mm or more in diameter (odds ratio [OR] = 46.5, 95% confidence interval [CI] = 11.4-190.8). Other risk factors were red hair (OR = 5.4, 95%CI = 1.0-28.4); blue eyes (OR = 4.5, 95%CI = 1.5-13.6); inability to tan after prolonged sun exposure (OR = 4.7, 95%CI = 0.9-24.6); heavy facial freckling (OR = 3.2, 95% CI = 0.9-12.3); and family history of melanoma (OR = 4.0, 95%CI = 0.8-18.9). Only 2 of 147 cases tested had germline variants or mutations in CDKN2A. There was no association with sunscreen use overall, however, never/rare use of sunscreen at home under the age of 5 years was associated with increased risk (OR = 2.2, 95%CI = 0.7-7.1). There was no difference between cases and controls in cumulative sun exposure in this high-exposure environment. Factors indicating genetic susceptibility to melanoma, in particular, the propensity to develop nevi and freckles, red hair, blue eyes, inability to tan and a family history of the disease are the primary determinants of melanoma among adolescents in this high solar radiation environment. Lack of association with reported sun exposure is consistent with the high genetic susceptibility in this group.
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PMID:Melanoma in adolescents: a case-control study of risk factors in Queensland, Australia. 1185 91

Hereditary pancreatic cancer (PC) appears to be exceedingly heterogeneous, as evidenced by its association with a variety of integrally associated diverse cancers and/or differing mendelian inherited cancer syndromes, which include the Lynch syndrome II variant of hereditary nonpolyposis colorectal cancer, hereditary breast-ovarian cancer syndrome in families with the BRCA2 mutation, hereditary pancreatitis, Peutz-Jeghers polyposis and the familial atypical multiple-mole melanoma syndrome in families with the CDKN2A (p16) germline mutation. Because of this heterogeneity, we provide a conservative estimate that about 5% (1,460) of PC cases in the US annually are hereditary. Although this number is relatively small, members of hereditary PC families serve as excellent models for studying the etiology, natural history, biomarkers, pathogenesis, potential carcinogenic exposures and their perturbation of underlying genetic events, and treatment of PC. These individuals would benefit greatly from method(s) capable of detecting cancer at an early stage, and such knowledge would also be useful for improving the diagnosis of the much more common 'sporadic' form of PC.
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PMID:Hereditary pancreatic cancer. 1212 Feb 26

Melanocytic nevi are the most potent risk factors for melanoma yet identified. Variation in the nevus phenotype within a population is predominantly genetically determined. Genes that determine nevus expression may therefore act as low penetrance melanoma susceptibility genes. Rare germline mutations in CDKN2A predispose to melanoma and appear to be nevogenic, although the correlation between nevus phenotype and mutation status is poor. It is plausible that more common CDKN2A variants may influence both melanoma susceptibility and nevus susceptibility. Ala148Thr is a G to A missense polymorphism of CDKN2A, which is found in 4%-6% of the general population. We have investigated the role of Ala148Thr as a low penetrance melanoma or nevus susceptibility allele in two separate groups of individuals. The first was a sample of 488 adults recruited from 179 families of patients with the atypical nevus phenotype and/or a family history of melanoma, and the second was a population-based sample of 599 women. Similar prevalences of Ala148Thr (4.9% and 5.2%) were found in both samples but significant variation in the prevalence of the polymorphism was seen across geographic areas within England. There was no association between Ala148Thr status and nevus number or history of melanoma, and therefore the results did not support the hypothesis that the Ala148Thr variant is a low penetrance melanoma or nevus susceptibility allele. A significant protective role of Ala148Thr on the number of atypical nevi was observed in the family sample (mean of 1 atypical nevus in those with the allele and 3.5 nevi in those without, p = 0.02). After allowing for potential confounders this was not evident in the population-based sample.
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PMID:An assessment of the CDKN2A variant Ala148Thr as a nevus/melanoma susceptibility allele. 1240 45

CDKN2A is regarded as a major melanoma susceptibility gene. A 19 bp deletion has been detected within Dutch families with familial atypical multiple mole-melanoma syndrome. Genetic analysis revealed two individuals with germline deletions in both copies of CDKN2A. One of them did not develop atypical naevi or melanoma, but died of adenocarcinoma at the age of 54 years. This report describes the results of the investigation of the second p16-null individual, who was also found to have glucose-6-phosphate dehydrogenase (G-6-PD) deficiency and who has developed many atypical naevi and seven melanomas. Using electron microscopic techniques, striking alterations in melanosomal structures and deviations in their sulphur, iron and calcium composition indicating a strong preference for phaeomelanogenesis and increased oxidative stress were found in the naevus cells of the patient. Using an in vitro model, we demonstrated that leaking melanin precursors may strongly enhance oxidative DNA damage through iron release from ferritin. We conclude that the homozygous p16 deletion is not sufficient for the development of a dysplastic naevus phenotype and melanoma. However, when an additional modifying factor, such as G-6-PD deficiency, increases the level of oxidative DNA damage in melanin-producing cells, the risk of developing atypical naevi and their malignant transformation may increase significantly.
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PMID:Homozygous germline mutation of CDKN2A/p16 and glucose-6-phosphate dehydrogenase deficiency in a multiple melanoma case. 1269 Mar 1

Rare mutations in the CDKN2A gene are highly penetrant for melanoma. Density of nevi is under strong genetic control and high density is a potent risk factor for melanoma. We used linkage and association analysis in adolescent twins from the UK to examine the hypothesis that the region containing the CDKN2A gene also contains a quantitative trait locus influencing normal nevus development. Five markers in the CDKN2A region were genotyped in 115 dizygotic twin pairs, and one marker (D9S942) was genotyped in 103 monozygotic twin pairs, all of whom had been phenotyped for nevus density. Linkage analysis showed no evidence of a quantitative trait locus influencing nevus density in this chromosomal region. A model partitioning the variation in phenotype into within- and between-twin pair components showed weak evidence of association between higher nevus density and longer mean length of the two D9S942 alleles (P=0.01). This relation, which was also observed in an earlier Australian twin study, could be because of the linkage disequilibrium between D9S942 and a neighbouring functional locus. Further investigation of this region is warranted in large-scale linkage or association studies.
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PMID:Linkage and association analysis of nevus density and the region containing the melanoma gene CDKN2A in UK twins. 1279 37

There are numerous risk factors for the development of malignant melanoma. It has been documented that genetic predisposition exists but exogenous factors are also very important. In familial melanomas it has been well established that mutation in the CDKN2A gene which is located at chromosome 9 leads to a marked risk for malignant melanoma. This tumor-suppressor gene is important for the regulation of the cell cycle and mutation in this gene is associated also with an increased rate of pancreas cancer. The penetrance of this mutation is influenced by UV-energy. In addition it has been shown that a second cluster for the familial atypical nevus syndrome is located at chromosome 1p36. Patients with the rare disease xeroderma pigmentosum have a defect in the DNA-repair mechanism inherited in an autosomal recessive trait and therefore develop within the first 20 years of life numerous malignant skin tumours including malignant melanomas. But also in non-syndromic patients a decrease of DNA-repair ability may occur. It has been shown recently that reduced DNA-repair ability is an independent risk factor for malignant melanoma and may contribute to susceptibility to sunlight-induced melanoma among the general population. Other constitutional risk factors for the development of malignant melanoma are fair skin, red hair and blue eyes. The most important exogenous risk factor is UV-exposition. Extensive and repetitive sunburns before the age of 15 years are especially predisposing to malignant melanoma. The most important preventive measures are continuous sun-protection including avoidance of sun in noon time on tropical and subtropical places, wearing a hut and sunglasses and application of sun-screens with high sun-protection factor. Furthermore a regular check for changing moles is indicated in persons with multiple atypical nevi or a familial melanoma syndrome. Nowadays molecular genetic screenings are available within research projects for members of melanoma-prone families. The controversy of such possibilities is discussed.
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PMID:[Genetic counseling and DNA testing in patients with increased risks for malignant melanoma]. 1450 54

The incidence of malignant melanoma has rapidly increased in recent years. Evidence points to the role of inheritance in melanoma development, but specific genetic risk factors are not well understood. Recent reports indicate a high prevalence of somatic mutations of the BRAF gene in melanomas and melanocytic nevi. Here we report that germ-line single nucleotide polymorphisms (SNPs) in BRAF are significantly associated with melanoma in German males, but not females. At-risk haplotypes of BRAF are shown. Based upon their frequencies, we estimate that BRAF could account for a proportion attributable risk of developing melanoma of 4% in the German population. The causal variant has yet to be determined. The burden of disease associated with this variant is greater than that associated with the major melanoma susceptibility locus CDKN2A, which has an estimated attributable risk of less than 1%.
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PMID:Polymorphisms of the BRAF gene predispose males to malignant melanoma. 1461 74

Putative tumour suppressor genes CDKN2A and CDKN2B (on chromosome 9p21) and CDKN2A-interacting cell growth regulatory genes CDK4 and Id-1 have been demonstrated to be involved in the pathogenesis of malignant melanoma (MM). Mutation analysis of these candidate genes was performed in MM families from southern Italy with three or more affected members or two affected members and one or more relative with histologically diagnosed atypical naevus. Two CDKN2A mutations, Arg24Pro and 1-292 G>A, were observed in two (15%) families; except for CDKN2A and Id-1 polymorphisms, no sequence variations were detected in the remaining genes. Screening among 119 sporadic MM cases revealed two additional CDKN2A mutations at very low prevalences. Identification of a large shared haplotype at 9p21 in some MM families negative for CDKN germline mutations suggests that other CDKN-inactivating mechanisms may be responsible for MM predisposition or, alternatively, additional susceptibility gene(s) may be present on chromosome 9p21. Fluorescence in situ hybridization analysis of a subset of MM tissue sections seemed to indicate that the D9S171 locus may be involved in MM pathogenesis.
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PMID:Mutation analysis of candidate genes in melanoma-prone families: evidence of different pathogenetic mechanisms at chromosome 9P21. 1464 20


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