PROGNOSTIC RELEVANCE OF A NOVEL PROLIFERATION MARKER, KI-S11, FOR SOFT-TISSUE SARCOMA - A MULTIVARIATE STUDY

In 132 soft-tissue sarcomas and 52 benign soft-tissue tumors, cellular proliferation was examined by immunohistochemistry using monoclonal a ntibodies Ki-S11 (Ki-67 antigen) and Ki-S1 (topoisomerase II alpha) an d by flow cytometric analysis of the S-phase fraction (SPE). Malignant tumors were graded histologically according to the Federation Nationa le des Centres de Lutte Contre le Cancer (FNCLCC) system. Patient age, sex, tumor location, histological type, and DNA ploidy were considere d as additional prognostic variables. Consistent immunoreactivity was seen in approximately 95% of the cases, and determination of SPF was p ossible in approximately 60%. Ki-S11 and Ki-S1 immunolabeling indices correlated in a linear manner. All proliferation parameters yielded si gnificant differences between benign and malignant tumors. Ki-S11 and Ki-S1 immunoreactive scores also co-varied significantly with SPF, mit otic count, and histopathological grade. In univariate analysis, immun ohistochemical proliferation indices, histopathological grade, mitotic count, and SPF were predictive of overall survival and the developmen t of metastases. In multivariate analysis, immunolabeling scores of pr oliferation markers, grade, and SPF emerged as independent predictors of global survival and systemic progression. We conclude that the immu nohistochemical assessment of proliferation, being more readily perfor mable and more easily assessable than the equally relevant S phase fra ction, may add appreciable information to the current prognostic model s for soft-tissue sarcoma.