EXPRESSION OF PROLIFERATING CELL NUCLEAR ANTIGEN (PCNA) AND KI-67 IN SOFT-TISSUE SARCOMA - IS PROGNOSTIC-SIGNIFICANCE HISTOTYPE-SPECIFIC

Abnormal patterns of proliferation characterize the behavior of many t umors. Proliferating cell nuclear antigen (PCNA) and Ki-67 are two cel l cycle antigens which are expressed in proliferative states. Our stud y examines the prognostic value of these cell-cycle antigens in soft t issue sarcoma (STS). Paraffin-embedded primary tumor tissues from 185 patients (1980-92) were stained with the anti-PCNA antibody PC-10; 182 of these were stained with the antibody MIB-1 for Ki-67. Using PCNA ( less than or equal to 50; >50%) and Ki-67 (less than or equal to 10; > 10%) indices, we examined and compared metastasis-free survival (MFS) in a mixed-histotype group, as well as after subdivision into MFH and non-MFH groups. Fifty-seven patients developed metastases. The median follow-up for survivors was 6 (2-13) years. In the mixed series, the 2 -year MFS for a PCNA index less than or equal to 50 was 76%, and for a n index >50 56%. Survival predicted by Ki-67 index was comparable. PCN A index (but not Ki-67) strongly correlated with the incidence of meta stasis in MFH tumors and predicted 2-year MFS of 81 vs 48%. In contras t, Ki-67 index (but not PCNA) strongly correlated with metastasis in n on-MFH tumors and predicted 2-year MFS survival of 90 vs 45%. No corre lation existed between PCNA and Ki-67 indices in the mixed histotype, MFH or non-MFH groups. In combination, a high PCNA and Ki-67 index cor related with poor survival, a high PCNA and lower Ki-67 index (or vice versa) with an intermediate survival, and low PCNA and Ki-67 indices with the best survival. The pattern of PCNA and Ki-67 expression raise s the possibility of histotype specificity.