Low Prevalence of Germline CDKN2A and CDK4 Mutations in Patients With Early-Onset Melanoma

Tsao, Hensin; Zhang, Xue; Kwitkiwski, Kimberly; Finkelstein, Dianne M.; Sober, Arthur J.; Haluska, Frank G.

doi:10.1001/archderm.136.9.1118

Cited by 72 publications

(44 citation statements)

References 33 publications

(34 reference statements)

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“…To date, p16 INK4a germline mutations were characterised in only two out of 55 MM patients less than 30 years, but that both had a history of familial melanoma (Whiteman et al, 1997;Tsao et al, 2000). Together with our data, this shows that the INK4a-ARF gene is rarely involved in genetic predisposition to melanoma in young patients with no familial history of melanoma.…”

Section: Discussionsupporting

confidence: 71%

Germline mutations of the INK4a-ARF gene in patients with suspected genetic predisposition to melanoma

et al. 2004

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Germline anomalies of the INK4a-ARF and Cdk4 genes were sought in a series of 89 patients suspected of having a genetic predisposition to melanoma. Patients were selected based on the following criteria: (a) familial melanoma (23 cases), (b) multiple primary melanoma (MPM; 18 cases), (c) melanoma and additional unrelated cancers (13 cases), (d) age at diagnosis less than 25 years (21 cases), and (e) nonphoto-induced melanoma (NPIM; 14 cases). Mutations of INK4a-ARF and Cdk4 were characterised by automated sequencing, and germline deletions of INK4a-ARF were also examined by real-time quantitative PCR. Seven germline changes of INK4a-ARF, five of which were novel, were found in seven patients (8%). Four were very likely to be pathogenic mutations and were found in three high-risk melanoma families and in a patient who had a pancreatic carcinoma in addition to melanoma. Three variants of uncertain significance were detected in one MPM patient, one patient o25 years, and one NPIM patient. No germline deletion of INK4a-ARF was found in 71 patients, and no Cdk4 mutation was observed in the 89 patients. This study confirms that INK4a-ARF mutations are infrequent outside stringent familial criteria, and that germline INK4a-ARF deletions are rarely involved in genetic predisposition to melanoma.

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Section: Discussionsupporting

confidence: 71%

Germline mutations of the INK4a-ARF gene in patients with suspected genetic predisposition to melanoma

et al. 2004

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“…Then 40 g of protein (assayed with the Bio-Rad protein reagent) from each extract was separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis with precast, 4 to 20% gradient polyacrylamide gels (Bio-Rad). Gels were electrotransferred to nitrocellulose paper, and proteins were detected with antibodies specific for p16 INK4A exon 2 was performed as described previously (68). DNA from 3 ϫ 10 5 to 1.5 ϫ 10 6 cells was isolated with the Qiagen DNeasy tissue kit (Qiagen Inc., Valencia, Calif.).…”

Section: /P14mentioning

confidence: 99%

A Two-Stage, p16^INK4A- and p53-Dependent Keratinocyte Senescence Mechanism That Limits Replicative Potential Independent of Telomere Status

Rheinwald

Hahn

Ramsey

et al. 2002

Molecular and Cellular Biology

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312

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With increasing frequency during serial passage in culture, primary human keratinocytes express p16 INK4A(p16) and undergo senescence arrest. Keratinocytes engineered to express hTERT maintain long telomeres but typically are not immortalized unless, by mutation or other heritable event, they avoid or greatly reduce p16 expression. We have confirmed that keratinocytes undergo p16-related senescence during growth in culture, whether in the fibroblast feeder cell system or in the specialized K-sfm medium formulation, and that this mechanism can act as a barrier to immortalization following hTERT expression. We have characterized the p16-related arrest mechanism more precisely by interfering specifically with several regulators of cell cycle control. Epidermal, oral mucosal, corneal limbal, and conjunctival keratinocytes were transduced to express a p16-insensitive mutant cdk4 (cdk4 R24C ), to abolish p16 control, and/or a dominant negative mutant p53 (p53DD), to abolish p53 function. Expression of either cdk4 R24C or p53DD alone had little effect on life span, but expression of both permitted cells to divide 25 to 43 population doublings (PD) beyond their normal limit. Keratinocytes from a p16؉/؊ individual transduced to express p53DD alone displayed a 31-PD life span extension associated with selective growth of variants that had lost the wild-type p16 allele. Cells in which both p53 and p16 were nonfunctional divided rapidly during their extended life span but experienced telomere erosion and ultimately ceased growth with very short telomeres. Expression of hTERT in these cells immortalized them. Keratinocytes engineered to express cdk4 R24C and hTERT but not p53DD did not exhibit an extended life span. Rare immortal variants exhibiting p53 pathway defects arose from them, however, indicating that the p53-dependent component of keratinocyte senescence is telomere independent. Mutational loss of p16 and p53 has been found to be a frequent early event in the development of squamous cell carcinoma. Our results suggest that such mutations endow keratinocytes with extended replicative potential which may serve to increase the probability of neoplastic progression.The replicative life span of normal human fibroblasts is limited by a senescence mechanism that responds to partial telomere shortening by triggering a p53-and p21 cip1 (p21)-dependent growth arrest (5,8,12). Expression of hTERT, the telomerase catalytic subunit, in presenescent fibroblasts and several other cell types, including retinal pigmented epithelial cells, vascular endothelial cells, and mesothelial cells, is sufficient to permanently evade this senescence mechanism and immortalize these cell types (7,17,78). Recent studies have indicated, however, that telomere shortening alone cannot completely explain the replicative life span limit and immortalization barrier exhibited by a diverse set of epithelial cell types.For keratinocytes (17, 31), mammary epithelial cells (11,21,31,56), bladder urothelial cells (51), and prostate epithelial cells (28, 57)...

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“…In a study of children aged less than 15 years with melanoma only 1/31 cases tested carried a CDKN2A mutation and this individual had a strong family history of melanoma (Whiteman et al, 1997). Similarly, screening of a cohort of 147 adolescents aged 15-19 years with melanoma found mutations in only two cases (Youl et al, 2002), and in a clinic-based series of melanoma cases younger than 40 years of age, 1/49 patients was found to carry a mutation and this individual had a very strong family history of the disease (Tsao et al, 2000). In another group that one would expect to be more genetically predisposed to melanoma, namely cases that have developed more than one primary tumour, the mutation frequency has also proved to be relatively low.…”

Section: Cdkn2amentioning

confidence: 99%

Genetics of melanoma predisposition

2003

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Low Prevalence of Germline CDKN2A and CDK4 Mutations in Patients With Early-Onset Melanoma

Cited by 72 publications

References 33 publications

Germline mutations of the INK4a-ARF gene in patients with suspected genetic predisposition to melanoma

Germline mutations of the INK4a-ARF gene in patients with suspected genetic predisposition to melanoma

A Two-Stage, p16^INK4A- and p53-Dependent Keratinocyte Senescence Mechanism That Limits Replicative Potential Independent of Telomere Status

Genetics of melanoma predisposition

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Low Prevalence of Germline CDKN2A and CDK4 Mutations in Patients With Early-Onset Melanoma

Cited by 72 publications

References 33 publications

Germline mutations of the INK4a-ARF gene in patients with suspected genetic predisposition to melanoma

Germline mutations of the INK4a-ARF gene in patients with suspected genetic predisposition to melanoma

A Two-Stage, p16INK4A- and p53-Dependent Keratinocyte Senescence Mechanism That Limits Replicative Potential Independent of Telomere Status

Genetics of melanoma predisposition

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A Two-Stage, p16^INK4A- and p53-Dependent Keratinocyte Senescence Mechanism That Limits Replicative Potential Independent of Telomere Status