Prognostic significance of a novel proliferation marker, anti-repp 86, for endometrial carcinoma: a multivariate...

Traditional prognostic factors often fail to identify a subgroup of endometrial carcinoma (EC) patients with an apparently paradoxical poor outcome. We therefore analyzed tumor cell proliferation immunohistochemically in a series of 164 endometrial carcinomas (EC) and compared its prognostic impact with that of the standard prognostic factors patient age, FIGO stage, FIGO grading, and histopathologic subtype. In addition to the established proliferation markers Ki-S5 (Ki-67) and KiS4 (topoisomerase IIalpha), we used a novel monoclonal antibody (MAb), anti-repp 86, which binds to a recently described proliferation-specific protein (p86) expressed exclusively in the S, G2, and M phases of the cell cycle. anti-repp 86, Ki-S4, and Ki-S5 immunoreactive labeling indices (LI) correlated significantly with FIGO stage, FIGO grade, and myometrial invasion, but not with histopathologic subtype. By univariate analysis, conventional prognostic factors and proliferation indices were all predictive of disease-related mortality. A multivariate Cox regression analysis selected anti-repp 86 LI (P = .002), FIGO stage (P = .02), and histopathologic type as significant prognosticators of recurrence; anti-repp 86 LI (P = .001) and histopathologic type (P = .0106) also emerged as relevant predictors of mortality. A hierarchical forward regression model with the conventional prognosticators entered first and with anti-repp 86 entered next showed that anti-repp 86 and histopathologic subtype were the superior independent prognostic indicators for an increased risk of recurrence and cancer-related death. We conclude that the evaluation of anti-repp 86 immunostaining is an easily performable and exceptionally reliable method for identifying EC patients with adverse prognosis.