Expression of Ki-67 and Estrogen Receptor Beta in Primary Cutaneous Melanoma as a Potential Indicator of Regional Lymph Node Positivity

: In the early stages of cutaneous malignant melanoma (MM), it is extremely difficult to predict adequately the risk from hematogenic and lymphatic metastasis. We investigate whether the immunohistochemical expression of Ki-67 and estrogen receptor beta (ERβ) in cells of MM could predict the status of regional lymph nodes. A total of 55 tissue samples of primary cutaneous melanomas with known status of regional lymph nodes were retrospectively evaluated for Ki-67 and ERβ expression by quantitative immunohistochemistry and then correlated with the status of regional lymph nodes and relevant clinicopathologic parameters. The ERβ-positive expression was detected in 38 of 55 tumors (69.09%). The Clark level showed a strong correlation with ERβ expression, as well as pT stage. All cases of MM showed Ki-67-positive expression and an elevated Ki-67 expression was strongly associated with increased Breslow thickness, Clark level, ulceration, lymphovascular invasion, number of mitosis, and pT stage. Logistic regression analysis showed that when ERβ levels increase by 1%, the risk of positive lymph nodes decreases by 7% (odds ratio=0.930; 95% confidence interval, 0.87-0.99; P=0.036), and, when the Ki-67 expression increases by 1%, the risk of lymph nodes' positivity increases by 10% (odds ratio=1.108; 95% confidence interval, 1.02-1.19; P=0.009). Correlation between expression of Ki-67 and ERβ and the status of lymph nodes has better prognostic significance than the relationship between melanoma thickness and the status of lymph nodes. Our study showed a significant prognostic value of Ki-67 expression in predicting the behavior of MM and the potential prognostic significance of ERβ.