Tumor angiogenesis and its possible role in intravasation of colorectal epithelial cells

Purpose: To determine whether an increase in tumor angiogenesis facilitates intravasation of colorectal epithelial cells, we compared intratumoral mic rovessel counts with the presence of circulating colorectal epithelial cell s in the portal venous blood from patients with colorectal carcinomas, Experimental Design: Circulating colorectal epithelial cells were detected by a reverse transcription-PCR assay to amplify guanylyl cyclase C (GCC) tr anscripts. The extent of tumor vascularization was quantitatively assessed by immunohistochemical staining with anti-CD31 antibody. Results: Colorectal epithelial cells las measured by GCC mRNA expression) w ere detected in the portal venous blood in 30 of 58 patients (52%). The mea n (+/- SD) microvessel count in the tumors from patients with expression of GCC mRNA in their portal venous blood was 82.74 +/- 24.97, The correspondi ng values in the tumors from patients without expression of GCC mRNA in por tal venous blood was 65.96 +/- 19, For each 10-microvessel increase per x20 0 field, the risk of colorectal epithelial cell presence in the portal veno us blood increased 1.52-fold (95% confidence interval, 1.19-2.12; P = 0.005 ), Conclusion: High intratumoral vessel count was noted to be a valuable facto r for predicting the presence of colorectal epithelial cells in the portal venous blood.