Thymidine phosphorylase (TP)/
platelet-derived endothelial cell growth factor, stimulates chemataxis of endothelial cells and is involved in the angiogenesis of human solid tumours. In this study we investigated tissue sections from 93
breast carcinomas for the immunohistochemical expression of
thymidine phosphorylase protein and in relationship to several clinicopathological parameters. The possible relationship to tumour neovascularization,
VEGF expression, extracellular matrix components (
tenascin,
fibronectin,
collagen type IV and
laminin) and
cathepsin D was also estimated. Nuclear and/or cytoplasmic TP expression was observed in tumour cells. Immunoreactivity was also often present in the stroma, endothelium and tumour-associated macrophages. High cytoplasmic TP expression, was observed in 35.5%, moderate in 30.1%, mild in 18.3%, while 16.1% of the cases were negative for TP expression. Moderate and high nuclear TP expression was observed in 30.1% of the tumours, low in 43%, while 26.9% did not show nuclear TP expression. High tumour stroma TP expression was expressed in 23.7% of the cases, moderate in 21.5%, mild in 45.2%, while 9.7% did not show stromal TP expression. TP expression did not correlate with the conventional clinicopathological features as well as with the microvessel density and the
VEGF expression. Patients with high levels of tumour cell TP expression were significantly associated with a favorable outcome in univariate method of analysis. A positive correlation of TP expression with
Cathepsin D expression was noticed. In addition, tumour cell TP expression was correlated with the extracellular matrix component
tenascin, while stromal cell TP expression was correlated with the growth fraction of the tumour. Our data suggests that TP expression does not seem to affect directly the neovasculatur of
breast carcinoma, although it seems to be implicated in the remodeling of
breast cancer tissue, through the interaction with other extracellular matrix components or
proteolytic enzymes. In addition, tumour cell TP expression could be considered as a prognostic
indicator of
breast cancer patients.