Pawe³ Surowiak 1,2,3 , Verena Materna 2 , Katarzyna K³ak 4 , Marek Spaczyñski 4 , Manfred Dietel 2 , Glen Kristiansen 2 , Hermann Lage 2 , Maciej Zabel 1,5 Prognostic Value of Immunohistochemical Estimation of CD24 and Ki67 Expression in Cisplatin and Paclitaxel Treated Ovarian Carcinoma Patients * 1 Chair and Department of Histology and Embryology, University School of Medicine, Wroc³aw, 2 Institute of Pathology, Charité Campus Mitte, Berlin, Germany, 3 Lower Silesian Centre of Oncology, Wroc³aw, 4 Chair and Department of Obstetrics and Gynaecology, University School of Medicine, Poznañ, 5 Chair and Department of Histology and Embryology, University School of Medicine, Poznañ CD24 is a small membranous protein which may participate in invasion of tumor cells. Present study aimed at evaluation of prognostic significance linked to immunohistochemical demonstration of CD24 expres- sion and the proliferation index, Ki67 expression in ova- rian cancers. The immunohistochemical reactions with monoclonal CD24- and Ki67-specific antibodies were performed in paraffin sections originating from 30 pa- tients with ovarian cancer treated using cisplatin and paclitaxel. Results of the reactions and analysis of the clinical course of the patients were subjected to statisti- cal analysis. Cases with cytoplasmic-membranous ex- pression of CD24 (CD24c-m) were found to exhibit sig- nificantly shorter overall survival time (P=0.0002) and progression-free period (P=0.0005). Cases with mem- branous expression of CD24 (CD24m) manifested a lon- ger overall survival time (P=0.022). No relationship was disclosed between expression of Ki67 on the one hand and survival time and CD24 expression on the other. As documented using chi square test, expression of CD24c-m predisposed to relapses (P=0.012), progression (P=0.0362) and to death (P=0.0034). Deaths were encountered sig- nificantly less frequently in cases with CD24m expres- sion (P=0.0465). The studies demonstrated that CD24c-m represented a strongly unfavorable prognostic indica- tor. The antigen represents an interesting target in the search for novel therapeutic methods. The more aggres- sive course of cases with CD24c-m expression was not linked to more intense proliferation of the tumor cells. Introduction Ovarian cancers are the most frequent gynecological tumors of female sex. Due to their location and, linked to it, late diagnosis as well as due to the aggressive course of the disease, therapy of ovarian cancer seldom leads to cure. De- spite introduction of new therapeutic modalities, proportion of 5-year survival for all clinical stages of the cancer in the recent 20 years did not exceed 40%. Seventy-five % of all ovarian cancer cases are diagnosed at the III or IV FIGO stage. In the groups only about 20% of the patients survive 5 years [7]. Therefore, in several centers intense search con- tinues for new prognostic indices, which would permit in- tensification of therapy in high risk cases and which could provide target for novel therapeutic modalities. Membranous CD (cluster of differentiation) proteins were originally described as specific markers of various sub- types of lymphoid cells. At present, expression of individual CD antigens provides grounds for classification of hemato- logical tumors [6]. In recent years, some of the CD antigens have been demonstrated also on cells of epithelial tumors and a proportion of them have manifested a significant relation- ship to the clinical course of the disease [12, 13, 15]. CD24 is a small membranous protein, typical for lympho- cytes B [14]. Expression of the protein was demonstrated also in the course of the development of pancreas [2], brain [19] and in regenerating muscles [3]. The expression was noted also in several types of neoplasms [9–11]. In 2002 we de- scribed CD24 expression in ovarian cancers [8]. In studies 69 Pol J Pathol 2005, 56, 2, 69–74 PL ISSN 1233-9687 * The study was supported by the grant No. 3 PO5E 064 22 from the State Committee of Scientific Research, Poland.