Up-regulation of thymidine phosphorylase expression is associated with a discrete pattern of angiogenesis in ductal carcinomas in situ of the breast

Abstract

Angiogenesis is essential for tumour growth and metastasis. Although vascular density as a measure of angiogenesis is an important prognostic factor in invasive breast carcinoma, the mechanism of a switch to an angiogenic phenotype in ductal in situ breast carcinomas (DCIS) has yet to be identified. Nevertheless, two distinct vascular patterns have been reported in DCIS: a diffuse increase of stromal vascularity and a dense rim of microvessels close to the basement membrane of involved ducts. This suggests that tumour angiogenesis in invasive breast cancer arises from two different angiogenic pathways. Platelet-derived endothelial cell growth factor, now known to be thymidine phosphorylase (..