SDHD promoter mutations are rare events in cutaneous melanomas but SDHD protein expression is downregulated in advanced cutaneous melanoma

BACKGROUND: SDHD promoter mutations were reported in 4-10% of cutaneous melanomas. The advanced clinico-pathological and patient survival association with SDHD mutation and/or expression in cutaneous melanoma remains controversial. OBJECTIVES: To evaluate the presence of SDHD promoter mutations and SDHD protein expression in a melanoma series and its possible association with prognosis and survival of the patients. METHODS: We assessed SDHD promoter status in cutaneous melanomas (CM), ocular melanomas (OM) and melanoma cell lines, and the expression of SDHD protein by immunohistochemistry in CM and OM, and by western blot in melanoma cell lines. We explored the putative association between SDHD protein expression and clinico-pathological and prognostic parameters of melanoma. RESULTS: We detected 2% of SDHD promoter mutations in CM, but none in OM and cell lines. SDHD protein expression was present in all CM, in OM and in all CM and OM derived cell lines analysed. A significant association between lower SDHD mean protein expression and presence of ulceration and higher pT stage was found. CONCLUSIONS: SDHD promoter mutation seems to be a rare event in CM but SDHD lower expression might associate with worst prognostic features in CM.