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

Aims and background: Thickness and level of invasion are the main morpholog ical 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 stud ied p53, PCNA, Bcl-2 and P-gp expression in 49 primary cutaneous melanomas. Materials: We used the immunophosphatase APAAP immuno-histochemical method. The percentage of labeled cells (according to four classes of positivity: <5%; 5-25%; 25-50%; > 50%) and the localization of immunoreactivity were ex pressed for each marker. Statistical analysis was performed to determine th e correlations between markers and level or thickness of melanomas. Results: We found a good correlation between p53 expression and melanoma th ickness (P <0.005), PCNA and P-gp expression. No relationship was observed between Bcl-2 expression and the different variables considered or other ma rkers. Conclusions: Our data seem to indicate an unfavorable prognostic role of hi gher nuclear p53 expression. However, we believe that our results need to b e integrated with patients' clinical follow-up and with the study of the ex pression of these markers in benign melanocytic lesions to gain more accura te information about their prognostic significance.