Caspases and inhibitor of apoptosis proteins in cutaneous and mucosal melanoma: expression profile and clinicopathologic significance

SummaryMalignant melanoma is characterized by apoptotic dysfunction, presumably due to abnormal expression of caspases and inhibitor of apoptosis proteins. However, the expression status and clinicopathologic significance of caspases and inhibitor of apoptosis proteins in cutaneous and particularly in mucosal melanomas have not been established. We investigated the expression of the major caspases (CASP3, 6, 7, 8, 9, and 10) and inhibitor of apoptosis proteins (survivin, CIAP1, CIAP2, XIAP, and Livin) by immunohistochemistry in 52 primary cutaneous and 25 mucosal melanomas, and 24 common nevi. Clinicopathologic and prognostic significance was investigated by statistical analysis. Our data showed that the significantly up-regulated inhibitor of apoptosis proteins in primary cutaneous and mucosal melanomas as compared with nevus (P < .01) were survivin, CIAP1, CIAP2, and Livin. Percentage of cases with positive caspase or IAP immunostaining was not significantly different between primary cutaneous and mucosal melanomas or between lower- and higher-stage melanomas (P > .05). Tumor location (cutaneous versus mucosal), stage, and positive cytoplasmic and nuclear survivin staining correlated significantly with prognosis by univariate analysis (P < .01). Multivariate analysis by Cox regression model showed that the most useful prognostic indicators were tumor location (cutaneous versus mucosal, relative risk = 6.021, 95% confidence interval = 2.623∼13.821, P = .000), stage (relative risk = 4.129, 95% confidence interval = 1.817∼9.383, P = .001), and nuclear survivin staining (relative risk = 3.383, 95% confidence interval = 1.137∼10.008, P = .028).