Alteration of apoptosis-related proteins (Apaf-1, caspase-9, Bcl-2, p53, and Survivin) according to malignant progression in cutaneous melanocytic lesions

Background: Apoptosis protease activating factor-1 (Apaf-1), caspase-9, Bcl-2, p53, and survivin are important factors in the pathway of apoptosis, but their clinicopathologic significance remains unclear in human cutaneous melanoma. We investigated the expression of these proteins and their clinical value in human cutaneous melanocytic lesions. Methods: We performed an immunohistochemical analysis to examine the expression and distribution of Apaf-1, caspase-9, Bcl-2, p53, and survivin in 36 cases of malignant melanoma (22 cases of primary melanoma and 14 cases of metastatic melanoma) and 41 cases of melanocytic nevus. Results: The expression of p53 was significantly higher in malignant melanoma than in melanocytic nevus (p<0.01), however the expressions of Apaf-1 and caspase-9 were significantly lower in malignant melanoma compared with melanocytic nevus (p<0.01 and p=0.027, respectively). Also, there was a significant difference for Bcl-2 staining between primary melanomas and metastatic lesions (p=0.004). Nuclear staining for survivin were absent in nevus, but were positive in 14 of 36 melanomas (p<0.01). Conclusions: The altered expression of Apaf-1, caspase-9, p53, and survivin are considered to be related to malignant progression in human cutaneous melanocytic lesions. Loss of Bcl-2 can be considered as a prognostic marker of malignant melanomas.