High expression of endothelial cell nitric oxide synthase in peritumoral microvessels predicts increased disease-free survival in colorectal cancer.

We have previously shown that a high frequency of microvessels expressing endothelial cell nitric oxide synthase (ecNOS) in the area surrounding the primary tumor (peritumoral ecNOS-expressing microvessel density: PEMVD) is a favorable prognostic indicator in breast cancer. Studies of a retrospective material of 186 colorectal tumors (Duke's stage B) now show that PEMVD is a significant and independent prognostic indicator for disease-free survival also in these patients. These data reinforce our hypothesis that a high level of expression of ecNOS in microvessels in the tumor-adjacent area protects against tumor metastasis.