Prognostic impact of CD31 antigen expression in anal canal carcinoma.

Background/Aims: CD31 is a platelet endothelial cell adhesion molecule. Thus CD31 immunostaining of vascular endothelial cells can be used to measure degree of angiogenesis. As angiogenesis is necessary for tumor growth and metastasis, microvessels density could be a predictor of prognosis. The purpose of this study was to examine the relationship between CD31 value and standard pathologic parameters and prognosis of anal canal carcinoma. Methodology: Twenty-four patients with anal canal carcinoma were evaluated. Five-mum sections of formalin-fixed, paraffin-embedded tissue were tested with monoclonal anti-CD31 antibody. CD31 value is considered positive if more than 185 vessels/mm(2) were counted. Pearson's chi (2) test was employed to test for association between CD31 value and clinicopathological variables. Results: We found no correlation between CD31 value and histologic type, lymph node involvement, patients age and neoplastic relapse. Significant correlation was found between CD31 score and depth of parietal invasion. Conclusions: The relapse type could strengthen the hypothesis that increased vascularity promotes neoplastic dissemination. As angiogenesis could be used as prognostic indicator to determine patients who may be at higher risk for relapse, our results warrant further confirmation. Development of markers of angiogenic activity in anal canal carcinoma must be an integral part of proper clinical trials.