Immunohistochemical study of 49 cutaneous melanomas: p53, PCNA, Bcl-2 expression and multidrug resistance

Thickness and level of invasion are the main morphological elements for an approximate but not sufficiently sensitive prognostic evaluation of cutaneous melanomas. By using immunohistochemical methods it is possible to detect biological markers related to prognosis. We have studied p53, PCNA, Bcl-2 and P-gp expression in 49 primary cutaneous melanomas.

We used the immunophosphatase APAAP immunohistochemical method. The percentage of labeled cells (according to four classes of positivity: <5%; 5-25%; 25-50%; >50%) and the localization of immunoreactivity were expressed for each marker. Statistical analysis was performed to determine the correlations between markers and level or thickness of melanomas.

We found a good correlation between p53 expression and melanoma thickness (P <0.005), PCNA and P-gp expression. No relationship was observed between Bcl-2 expression and the different variables considered or other markers.

Our data seem to indicate an unfavorable prognostic role of higher nuclear p53 expression. However, we believe that our results need to be integrated with patients' clinical follow-up and with the study of the expression of these markers in benign melanocytic lesions to gain more accurate information about their prognostic significance.