Abstract: Objective To investigate the expressions of BAG-1, P53 and Bcl-2 proteins and their significance in malignant melanoma. Methods Biopsy samples were obtained from 32 patients with malignant melanoma and 20 patients with pigmented nevi, and paraffin embedded sections were prepared. The expressions of BAG-1, P53 and Bcl-2 proteins were examined with immunohistochemistry in these sections. The correlation between the immunohistochemical findings and clinical data （including age, gender, Clark level and presence of lymph node metastases） was also analyzed. The expression of BAG-1 protein in melanoma cell lines, M14 and B16F10, was assessed by immunocytochemistry. Results The expression rate of BAG-1 protein was 78% （25/32） in cutaneous malignant melanoma, 15% （3/20） in pigmented nevi; the difference was statistically significant （P < 0.01）. The expression of BAG-1 protein was positively correlated with Clark level of cutaneous malignant melanoma （r = 0.47, P < 0.05）, but not with the expressions of P53 or Bcl-2 （r = 0.05, 0.11, respectively, both P > 0.05）. Immunocytochemistry showed that BAG-1 protein was expressed in M14 and B16F10 cells. Conclusions The results indicate that BAG-1 protein is overexpressed in cutaneous malignant melanoma, and the overexpression is positively correlated with Clark level of malignant melanoma.

Key words: BAG-1 protein, Melanoma, p53, bcl-2