Study of borderline and invasive mucinous ovarian tumors using Ki-67 (MIB 1) antibodies and nucleolar organizer region (NOR) staining.

Abstract

Extensive application of new methods in histopathology has resulted in large quantities of data on molecular markers in different types of human tumors. The main purpose has been to obtain additional parameters for the characterization of various types of malignancy to give more precise information on their biological behavior. In this study we tested AgNOR and Ki-67 (MIB 1) staining in 39 ovarian mucinous tumors to evaluate its diagnostic potential in distinguishing between borderline tumors and well-differentiated carcinomas at stage I of FIGO classification. In general, there was an increase in AgNOR median values from benign (1.83 +/- 0.8) to well-differentiated carcinomas (2.91 +/- 1.3) with an intermediate value in borderline (2.3 +/- 1.6). The lowest Ki-67 labeling index (LI) was found in benign cystadenomas (5.7% +/- 3.4%) and papillary mucinous cystadenomas (7.9 +/- 5.8%). In borderline tumors mean LI was 12.2 +/- 10.9% whereas well-differentiated carcinomas had higher LI (16.8 +/- 10.2%). There were no statistically significant differences between the evaluated tumors and techniques applied. In our opinion the AgNOR count and Ki-67 LI do not appear useful for assessing differences between borderline and well-differentiated mucinous ovarian tumors at stage I of clinical advancement.