Expression of bcl-2 and p53 in Merkel cell carcinoma. An immunohistochemical study.

Bcl-2 is a protooncogene thought to play a role in oncogenesis by inhibiting programmed cell death. It may interact with p53, a tumor-suppressor gene which induces apoptosis in certain circumstances. We have studied these gene products by immunohistochemistry in 15 cases of Merkel cell carcinoma, a tumor characterised by prominent apoptosis. Five cases showed moderate/strong staining for p53, with moderate/strong bcl-2 staining in 10 patients. In seven cases abundance of p53 and bcl-2 expression was mutually exclusive. Two patients died within 1 year of diagnosis and six had nodal recurrences. Gene expression and survival appear unrelated. The role of Bcl-2 and p53 in tumorigenesis is complicated and may be inter-related with other genes known to be involved in programmed cell death.