ANGIOGENESIS IN COLORECTAL TUMORS - MICROVESSEL QUANTITATION IN ADENOMAS AND CARCINOMAS WITH CLINICOPATHOLOGICAL CORRELATIONS

Angiogenesis is a crucial step in tumor growth and progression. Its qu antitation by microvessel counting is of prognostic value in several t ypes of malignancies. Scarce data are available on angiogenesis in gas trointestinal tumors. We studied 36 adenomas and 178 large bowel carci nomas to evaluate the onset of angiogenesis in colorectal tumorigenesi s and to assess the prognostic significance of microvessel quantitatio n. Endothelial cells were immunostained with an anti-CD31 mAb; in each case three microscopic fields (x 200) with the highest number of micr ovessels were counted: the average value of the three fields was used to evaluate the significance of microvessel density (MVD). MVD of norm al mucosa (41 cases) served as controls. MVD was 42 +/- 10 in the norm al mucosa, 64 +/- 10 in adenomas, and 115 +/- 39 in carcinomas (normal versus adenomas, P < 0.001; adenomas versus carcinomas, P < 0.0001). The transitional mucosa adjacent to carcinomas displayed intermediate levels of MVD (89 +/- 23; P < 0.001 versus adenomas; P < 0.001 versus carcinomas). High MVDs were not associated with metastases, disease st age, and patient survival. The data indicate that angiogenesis is an e arly, critical step in colorectal tumorigenesis. MVD, however, does no t provide significant prognostic information in colorectal cancer pati ents.