OBJECTIVETo investigate the correlations among Ki-67 expression, mitosis and other clinicopathological parameters of primary cutaneous malignant melanoma, and search for prognostic factors of malignant melanoma.

METHODSTotally 127 cases of primary cutaneous malignant melanoma were collected from Beijing Cancer Hospital. Immunohistochemical study for Ki-67 was performed, and the mitosis was calculated referring to "hot spot" method recommended by the seventh edition of the American Joint Committee on Cancer (AJCC) melanoma staging system. The correlations of Ki-67 expression, mitosis and other clinicopathological parameters were analyzed, and the survival analysis of all these risk factors including TNM and Clark level was conducted based on follow up data.

RESULTSThe expression level of Ki-67 was associated with necrosis and Breslow thickness (P < 0.05). Mitosis was correlated with Clark level and Ki-67 expression (P < 0.05). Univariate analysis indicated Ki-67 expression level (P = 0.043), mitosis (P = 0.030) and TNM stage (P < 0.001) might influence the survival of patients. However, multivariate analysis showed that the TNM staging was the only independent prognostic factor affecting survival.

CONCLUSIONSThe prognosis of patients with primary cutaneous malignant melanoma was closely related to the TNM staging at the fist examination. Ki-67 expression and mitosis are two important clinicopathological parameters of primary cutaneous malignant melanoma.