Angiogenesis in advanced colorectal adenocarcinoma with special reference to tumoral invasion

Angiogenesis is a crucial step in tumor growth and progression. Its quantification by microvessel counting has a prognostic value in several types of malignancies and recently has been appraised in gastrointestinal tumors.

To assess the prognostic significance of microvessel quantification in colorectal carcinomas, studying its association with hematogenous metastases, survival and clinicopathological variables such as size, histologic differentiation and depth of tumoral invasion.

Forty eight patients with colorectal adenocarcinoma were included in this study. Histologic sections of invasion tumoral margin (4 microns) were analyzed and endothelined microvessels were immunostained with monoclonal mouse Von Willebrand Factor (anti-FVIII). The microvessel count was performed from the identification of the area with increased microvessel density--hot spots--and results of the mean in five of these fields.

The cut-off microvessel count was 14 microvessels/0.785 mm2, which divided the sample into hypovascular and hypervascular groups. While 2/8 (25%) tumors with muscularis propria invasion were classified as hypervascular, 11/15 (73%) tumors with serosa or perivisceral fat were classified as hypervascular. However, a non-significant statistical association was found between the angiogenesis quantification, hematogenous metastases, survival and clinicopathological variables such as size and histologic differentiation of the tumor.

The findings of significantly increase of microvessel count in conformity with tumoral invasion depth supports the hypothesis that tumor progression might be related to angiogenesis. Although angiogenesis is an important step in the tumoral growth and during the metastatization process, other factors can be implicated.