Practical application of angiogenesis and vasculogenic mimicry in prostatic adenocarcinoma

Tumor growth depends on vascular blood supply. The novel discovery of non-endothelialized vessel-like channels in malignant tumors called vasculogenic mimicry has provided new insights about tumor behavior and also serves as a potential target for drug therapy. Although the association between vasculogenic mimicry and poor prognosis has been established in some tumors, there are only a few studies concerning prostatic carcinoma.

Using a histochemical and immunohistochemical dual staining method for PAS-CD34 and special immunohistochemical staining for laminin, we studied the presence and pattern of non-endothelialized channels known as vasculogenic mimicry as well as the quantity of endothelialized vessels designated as microvessel density in usual paraffin sections of 20 low-grade and 20 high-grade prostatic adenocarcinomas by routine light microscopy.

We found a direct positive relationship between higher microvessel density and tumor grade (P<0.001), presence of vascular invasion (P<0.001) and percent of involved tissue (P<0.001); however, no such relationship was found with vasculogenic mimicry and only a weak correlation was noted between vasculogenic mimicry and perineurial invasion (P=0.03).

Unlike other cancers and despite the results of in vitro studies on prostatic adenocarcinoma, we were not able to demonstrate a significant relationship between vasculogenic mimicry channels and histologic grading as one of the most important prognostic factors; however, this may be due to an inherent limitation of prostatic tissue imposed by abundant smooth muscle fibers stained by this method. On the other hand, microvessel density scoring appears to be an important, simple, and applicable histologic tool for prostatic cancer evaluation in daily practice.