Low BRAF V600 mutation prevalence in primary skin nodular melanoma in Indonesia: A real-Time PCR detection among Javanese patients

Abstract

Background: Cutaneous melanoma is a rare, aggressive skin malignancy with a high mortality rate. Although only contributing 7.6% of the cases worldwide, Asia is responsible for 18.6% of deaths from cutaneous melanoma. BRAF V600 mutation presents a potential prognostic predictor in melanoma. Unfortunately, studies on that mutation in melanoma, particularly nodular subtype, in Indonesia are still scarce. This research aimed to investigate the prevalence of BRAF V600 mutation in primary skin nodular melanoma in Yogyakarta and Central Java, Indonesia. Its association with clinicopathological parameters was also analyzed. Methods: Forty paraffin-embedded tissue samples from primary skin nodular melanoma cases in 2011-2018 were collected from the two biggest referral hospitals in Yogyakarta and Central Java, Indonesia. The BRAF V600 mutation status was assessed using qualitative real-Time PCR and its associations with age, sex, anatomic location, lymph node metastasis, tumor thickness, ulceration, mitotic index, necrosis, lymphovascular invasion, and tumor-infiltrating lymphocytes were analyzed. Results: BRAF V600 mutations were found in 4 (10%) samples. These mutations were significantly associated with the central (non-extremity) region (p = 0.013) and presence of lymphovascular invasion (p = 0.005). However, it was not associated with any other variables analyzed in this study. Conclusion: The prevalence of BRAF V600 mutation in Indonesian primary skin nodular melanoma cases is low and significantly associated with anatomic location and lymphovascular invasion. It is lower than prevalences in other Asian populations as well as in Caucasian populations and suggests that melanoma cases in Javanese people may have distinct clinicopathological characteristics from other Asian ethnicities.