PROLIFERATION MARKERS AND PROGNOSIS IN MERKEL CELL-CARCINOMA

Merkel cell carcinoma (MCC) is a frequently aggressive primary cutaneo us neuroendocrine malignancy. We investigated 3 cell proliferation mar kers which may be useful in predicting the aggressiveness of MCC: 1) p 53, a tumor suppressor protein, 2) Ki-67, a marker of cell cycling, an d 3) proliferating cell nuclear antigen (PCNA). Twenty patients with M CC were studied. The 3 cell proliferation markers were studied by immu noperoxidase. Clinical and immunoperoxidase results were tabulated acc ording to recurrence or death from disease. Of the 20 patients, 10 exp erienced recurrence, and 10 did not. Seven tumors were positive for p5 3. We found correlations between recurrence and death in MCC patients, between p53 positivity and recurrence/death, and between p53 positivi ty and head/neck primary sites. We found no correlation with recurrenc e by gender or primary site. PCNA was positive in only 1 patient, whil e Ki-67 was positive in all patients, making these 2 markers unsuitabl e for predicting recurrence. Further clinical studies will be helpful to confirm and refine the application of this test. Prognostic informa tion from such studies may be useful in planning observation and treat ment for patients in the future.