The endothelial marker CD 34 in the assessment of tumour vascularisation in ovarian cancer

s. Objective: Tumour angiogenesis as well as the density of newly formed vessels are of potential prognostic relevance in the assessment of malignant neoplasia. Among other monoclonal antibodies the endothelial marker CD 34 is being increasingly investigated in the assessment of tumour vascularisation, especially in vascular tumours. The aim of this study was to determine the value of CD 34 as an immunohistochemical method to quantify tumour vascularisation in ovarian cancers. Methods: In a preliminary study 30 solid ovarian cancers were investigated with regard to their CD 34 expression. Paraffine embedded specimens were processed immunohistochemically using the PAP-method, in a dilution of the primary antibody CD 34 of 1:50. Morphological aspects, such as tumour homogenicity and vessel distribution, as well as vessel density were analysed. Results: The primary antibody CD 34 reacted positively with the endothelium of arteries, veins and capillaries, noting a more marked expression in small vessels. Furthermore, enhanced staining of those tumour sections with connective tissue was observed, very likely due to the increased vascular pattern of connective tissue. Non-homogenous distribution (e.g.,,hot spots) was also seen. Overall, an excellent marking and therefore quantification of tumour vessels was achieved using CD 34. Summary: In this pilot study we were able to demonstrate the ability of CD 34 to mark tumour vessels in solid cancers of the ovary. Whether this marker will be of any prognostic relevance in the future is under investigation in a larger patient cohort at present.