Comparison of methods of microvascular staining and quantification in prostate carcinoma: relevance to prognosis

High microvascular density in prostate carcinomas may indicate poor prognosis. Our aim was to compare two different anti-endothelial antibodies and two different ways of evaluating microvascular scores in hot spots (microvessel density (MVD) and Chalkley counts). Adjacent serial sections of formalin-fixed, paraffin-embedded tumor specimens from TURPs on 51 consecutive patients with prostate carcinoma were immunostained for CD34 and von Willebrand Factor (vWF). Estimates of microvascular density were based on projecting a 10 x 10 grid or a Chalkley grid onto a vascular hot spot of the invasive prostate carcinoma. Anti-CD34 antibodies stained microvessels in all 51 tumors, whereas anti-vWF antibodies in 6 tumors resulted in intense background staining causing omission of these. Anti-CD34 antibodies highlighted significantly more microvessels than anti-vWF antibodies, and the anti-CD34 vascular scores with either of the counting methods were significantly correlated, which was not the case with vWF. Both grids used on anti-CD34-stained sections resulted in vascular scores that could separate the tumors into prognostic groups. This was not possible using the Chalkley grid on vWF-stained tumors. In conclusion, anti-CD34 antibodies are sensitive endothelial markers in prostate carcinoma, and the investigated counting methods are compatible. Moreover, high vascular scores seem to carry a poor prognosis.