p53 expression in sweat gland tumors.

We analyzed the expression of p53 in 74 cutaneous adnexal tumors, with enhancement of the detection by incubation of the slides in the microwave. The immunostaining in benign tumors was almost uniformly negative as we found p53-positivity only in one poroma, one nodular hidradenoma, and one case of syringocystadenoma papilliferum (amongst 13 spiradenomas, 9 cylindromas, 12 nodular hidradenomas, 7 poromas, 6 syringomas, 7 syringocystadenomas papilliferum, 2 papillary tubular adenomas and 4 chondroid syringomas). These results contrasted with the widespread p53 overexpression, which was revealed in the sweat gland carcinomas. All spiradenocarcinomas (3), malignant nodular hidradenoma (1), apocrine hidradenocarcinoma (1), and malignant syringoadenoma (1) showed a strong reaction to anti-p53 antibody. Two of three eccrine hidradenocarcinomas, and two of three porocarcinomas presented p53 overexpression, whereas in one case of malignant cylindroma and adenoid cystic carcinoma we did not find p53-positivity. The results of the study indicate an important role, that p53 protein plays in the malignant sweat gland tumors in comparison to their benign counterparts, but reveal that its overexpression may also occur in the reactive and benign neoplastic processes.