FOCAL EXPRESSION OF THYMIDINE PHOSPHORYLASE ASSOCIATES WITH CD31 POSITIVE LYMPHOCYTIC AGGREGATION AND LOCAL NEO-ANGIOGENESIS IN NONSMALL CELL LUNG-CANCER

Platelet-derived endothelial cell growth factor (PD-ECGF) also called thymidine phosphorylase (TP) has been shown to have considerable angio genic activity. 141 cases of early stage non-small cell lung cancer we re stained for TP and vascular grade using the P-GF.44C and JC70 MoAbs , respectively The early steps of TP activation could be identified in 27 cases, where one or two foci of cancer cell TP overexpression occu rred within a general pattern of negative/weak staining. Thirty-three foci of overexpression were analyzed for the local microvessel density in the adjacent stroma, assessed by microvessel counting (MC) and Cha lkley Score (CS) comparatively with the remaining TP negative tumor ar eas. The degree of local inflammatory (lymphocyte and macrophage) infi ltration was also assessed. A statistically significant increase of me an MC and mean CS was observed in areas of TP overexpression in both l ow and high angiogenesis cases Overall the mean MC in overexpressing a reas, assessed in 250x fields, was 20.4 +/- 12.8 vs. 13.6 +/- 9.5 in a reas with no TP expression (p=0.0001). The mean CS was 5.7 +/- 3.3 and 4.0 +/- 2.1, respectively (p=0.0003). Ten out of 19 (54%) cases with low lymphocytic infiltration showed marked stromal lymphocytic infiltr ation in the area of focal TP overexpression (p=0.01). The present stu dy provides further evidence of a direct association of TP and the pro cess of angiogenesis in non-small cell lung cancer.