Genetic Characteristics of Primary Cutaneous Malignant Melanoma in Koreans Compared With Western Populations.

Background/aim: Cutaneous melanoma, a melanocyte malignancy, can be divided into many clinical subtypes that differ in presentation, demographics, and genetic profile. In this study, we used next-generation sequencing (NGS) analysis to review genetic alterations in 47 primary cutaneous melanomas in the Korean population and compared them to alterations from melanomas in Western populations.

Patients And Methods: We retrospectively reviewed clinicopathologic and genetic features of 47 patients diagnosed with cutaneous melanomas between 2019-2021 at Severance Hospital, Yonsei University College of Medicine. NGS analysis was performed at diagnosis to evaluate single nucleotide variations (SNVs), copy number variations (CNVs), and genetic fusions. Genetic features in Western cohorts of melanoma were then compared with previous studies performed in the USA: Cohort 1 (n=556), Cohort 2 (n=79), and Cohort 3 (n=38).

Results: The most common histological classification of melanoma was the acral lentiginous type (23/47, 48.9%). BRAF V600 mutation was most frequent (11/47, 23.4%), but was significantly lower compared to Cohort 1 (240/556, 43.2%) and Cohort 2 (34/79, 43.0%) (p=0.0300). CNV analysis identified amplifications in chromosomes 12q14.1-12q15 (11/47, 23.4%) including CDK4 and MDM2 genes and 11q13.3 (9/47, 19.2%) including CND1, FGF19, FGF3, and FGF4 genes more frequently in the present study population than Cohort 1 (p<0.0001).

Conclusion: These results clearly demonstrated differences in genetic alterations between melanomas in Asian and Western populations. Therefore, BRAF V600 mutation should be considered a significant signaling pathway explaining melanoma pathogenesis occurrence in both Asian and Western populations, whereas loss of chromosome 9p21.3 is unique to melanomas in Western populations.