p53 expression in cutaneous malignant melanoma: an immunohistochemical study of 87 cases of primary, recurrent, and metastatic melanoma.

Recent studies on the role of the p53 gene in human melanoma have largely been contradictory. To further assess p53 expression in melanoma, we have studied p53 immunoreactivity in 87 cases of primary, recurrent, and metastatic melanoma. Routine immunostaining was performed on paraffin sections with the monoclonal antibody PAb1801 and a streptavidin-biotin method. All specimens were blindly and independently assessed by two observers for number of melanoma cells with granular nuclear staining. Seven melanomas (8%) exhibited from 1 to 50% positive cells and another eight cases (9%) showed p53 immunoreactivity in < 1% of cells. All of the melanomas found to be positive for p53 with one exception (< 1.50 mm) were either thicker than 1.50 mm, recurrent, or metastatic. We conclude that these findings provide little evidence for significant p53 alteration in the initiation and development of melanoma.