THE EXPRESSION OF HLA CLASS-I ANTIGEN IN PROSTATE-CANCER IN RELATION TO TUMOR DIFFERENTIATION AND PATIENT SURVIVAL

The expression of HLA class I antigens was studied using the immunoper oxidase technique on 30 patients with prostate cancer and 29 patients with benign prostatic hypertrophy (BPH). Forty-three percent of the tu mors stained positive, in contrast to 21% of the BPH. An inverse relat ionship was noted between class I expression and degree of tumor diffe rentiation: 88% of the well-differentiated tumors (8/9) expressed clas s I antigen, compared with 33% (3/9) of the moderately differentiated and 16% (2/12) of the poorly differentiated tumors. No significant sur vival difference was found between those with class I-positive and -ne gative tumors. However, when both class I expression and degree of dif ferentiation were considered, those with positive tumors at each level of differentiation had better survival than those with negative tumor s. These data suggest that HLA class I expression may serve as a finit e prognostic factor and may have relevance in future immunotherapy.