Fas antigen expression and outcome of oral squamous cell carcinoma

Paraffin sections of biopsy specimens obtained from 46 patients with oral s quamous cell carcinomas were stained with both anti-peptide antibody agains t human Fas antigen and monoclonal mouse antibody against human proliferati ng cell nuclear antigen (PCNA). The patients received chemotherapy with a c ombination of carboplatin and peplomycin sulfate or mitomycin C and peplomy cin sulfate before surgery. The relation between the expression of Fas anti gen and the clinical features of each case was examined. The correlation be tween PCNA and Fas antigen expression was also studied. The mean PCNA label ing index of the 22 Fas-negative cases was 46.9%, which was significantly h igher than that of the 24 Fas-positive cases (39.5%). Strong correlations w ere found between the expression of Fas antigen and the response to chemoth erapy, tumor recurrence, and survival. The Fas-negative group had only a mi nor response to chemotherapy and a poor outcome, whereas the Fas-positive g roup had a better response to chemotherapy and a good outcome. Although lym ph node metastasis was significantly related to survival, there was no corr elation between Fas antigen expression and lymph node metastasis. The Kapla n-Meier survival curve of patients positive for Fas antigen was significant ly better than that of patients negative for Fas antigen. Our results sugge st that Fas antigen expression is an independent predictor of outcome whose usefulness should be evaluated in prospective studies.