Here we report a novel germline mutation in exon 1 of the CDKN2A gene, E27X, which we first detected in melanoma patients living in or originally from a small geographic area bordering Liguria in north-western Italy.
Furthermore, we observed that a carrier of the founder CDKN2A [p.Leu113Leu;p.Pro114Ser] mutation as well as two MC1R moderate-risk variants, [p.Arg151Cys(+)p.Arg163Gln] developed 22 primary melanomas in the three years that followed initiation of levodopa therapy for Parkinson's disease.
The obtained results allow us to conclude: (i) survival times of 500 C/G carriers vs. cumulating proportion surviving was not statistically significant; (ii) CDKN2a polymorphism 500 C/G correlated with Ala148Thr; (iii) no correlation was observed between the 500 C/G polymorphism and age of diagnosis, localization of primary melanoma and survival time; (iv) we did not find correlation between 500 C/G and type of cancer in the family; (v) changes in the CDKN2a gene were not found in patients with second cancer.
No disease-related CDKN2A germline mutations were identified in any of the melanoma patients analysed but the previously described CDK4 mutation, Arg24His, was found in one patient with a family history of melanoma.
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.
The results of this study revealed a paucity of mutations in CDKN2A/ARF suggesting that in the Polish population this gene does not contribute significantly to early-onset breast cancer, pancreatic cancer and malignant melanoma.
The M53I mutation is the most common CDKN2A mutation identified in Scottish melanoma patients and is also found in a small number of families in other countries.
The results suggest that the relative risk of mutation carriers in the population may be lower than currently believed and that different mutations on the CDKN2A gene may confer substantially different risks of melanoma.
The variation in CDKN2A mutations for the four features across continents is consistent with the lower melanoma incidence rates in Europe and higher rates of sporadic melanoma in Australia.
This population based study of Icelandic melanoma cases and controls showed a frequency of disease related CDKN2A mutant alleles ranging from 0.7% to 1.0%, thus expanding our knowledge about the frequency of CDKN2A mutations in different populations.
Compared to SPM patients, the risk of harboring a CDKN2A mutation rose as the number of primary melanomas increased and was not influenced by family history.