The aspects of angiogenesis in anal canal carcinomas compared with that in colorectal carcinomas

To compare the angiogenesis in anal canal carcinomas (ACC) with that in colorectal carcinomas (CRC).

A number of 507 CRC, surgical specimens, were analyzed, 12 cases (1.97%) being ACC. In 20 cases from left and right colon (CRC) and in the 12 ACC we analyzed the immunohistochemical parameters related to angiogenesis, utilizing the following LabVision antibodies: CD31, CD105 (endoglin) and VEGF1. Morphometrical analysis and positive cell counting were performed in the tumoral and peritumoral tissue. Immunoperoxidase method was used.

The average age was 63.17 +/- 10.87 years in CRC, respectively 57.9 +/- 10.05 years in the ACC (p<0.0001). Compared with CRC the ACC occur more frequently at the females (58%). Angiogenesis was expressed in the majority of cases. In CRC, the microvascular density (MVD) was higher than that from ACC. The ratio CD31/CD105 was 1 in ACC and 3 in CRC. VEGF was positive in 25% of ACC and 80% of CRC. In CRC were more mature vessels, marked only with CD31 than immature vessels or endothelial isolated cells marked with both CD31 and CD105. In ACC prevailed the neoformed vessels marked with both CD31 and CD105.

The performed assessments have showed a higher incidence of ACC at females and at younger ages. The angiogenesis in ACC was not so high like in CRC and the immature neoformed vessels was more frequently. In ACC, the antiangiogenic treatment that regards the VEGF inhibition seems to be not as efficient as in CRC. The radiotherapy could stop the angiogenesis and could inhibit the vessels' maturation.