Abnormal patterns of proliferation characterize the behavior of many
tumors.
Proliferating cell nuclear antigen (
PCNA) and Ki-67 are two cell cycle
antigens which are expressed in proliferative states. Our study examines the prognostic value of these cell-cycle
antigens in
soft tissue 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 (< or = 50; > 50%) and Ki-67 (< or = 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 < or = 50 was 76%, and for an index > 50 56%. Survival predicted by Ki-67 index was comparable.
PCNA index (but not Ki-67) strongly correlated with the incidence of
metastasis in MFH
tumors and predicted 2-year MFS of 81 vs 48%. In contrast, Ki-67 index (but not
PCNA) strongly correlated with
metastasis in non-MFH
tumors and predicted 2-year MFS survival of 90 vs 45%. No correlation 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 correlated 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 raises the possibility of histotype specificity.