The retrospective molecular analysis of large or giant congenital melanocytic nevi in a group of Polish children.

BACKGROUND

Large and giant congenital melanocytic nevi (CMN), benign naevomelanocytic proliferations derived from neural crests, with a projected adult size (PAS) ≥ 20 cm, are connected to a high risk of melanoma and neurocutaneous melanosis. Among several factors, genetic alterations seem to be involved in tumorigenesis. The aim of the present study was to analyse the mutation status of and genes in resection specimens from large or giant CMN in a group of Polish patients.

MATERIAL AND METHODS

The formalin-fixed, paraffin-embedded resection specimens from 18 patients, fixed in the years of 2006 to 2017, were included in the study. The regions containing the highest load of melanocytes were macrodissected prior to DNA isolation. The and mutation status was evaluated using qPCR.

RESULTS

We detected activating mutations in gene (codons: 12 and 61) in 7 out of the 18 (38.9%) patients. No mutations were found.

CONCLUSION

Our study, the first molecular analysis of large/giant CMN in Polish patients, supports the hypothesis that mutation in codon 61 are frequent, recurrent mutations in large/giant CMN. Moreover, we show, for the first time, that mutations in codon 12 (p.Gly12Asp) can be also detected in giant CMN. The exact role of these genetic alterations in CMN formation remains to be elucidated.