P53 AND PCNA EXPRESSION IN MALIGNANT MELANOMAS OF THE HEAD AND NECK

Mutation in the p53 tumor suppressor gene is the most common genetic a lteration in human cancer. As in mutant p53 the protein is stabilised and the half-life is extended, it becomes detectable by immunohistolog ical staining. p53 immunoreactivity thus seems to be a potential bioma rker for the assessment of the oncogenic potential of malignant melano mas. In 103 tissue sections of primary and metastatic malignant melano mas of the head and neck detectable levels of p53 were only found in 3 of the primary tumors and in none of the metastases. At the same time the proliferation status of the malignant melanoma lesions was determ ined using the cell cycle specific antibody PCNA. 55 primary and metas tatic tumors were stained with a PCNA-MAb to determine the proliferati on activity of the tumors. The results of our immunohistochemical inve stigation suggest that immunoreactivity of p53 cannot be used to deter mine the malignant potential of melanomas in the head and neck. PCNA s taining showed that the majority of the tumors and metastases were pro liferating rapidly.