Immunohistochemical expression of thymidine phosphorylase/platelet-derived endothelial cell growth factor in squamous cell carcinoma of the esophagus.

BACKGROUND/AIMS: Thymidine phosphorylase (dThdPase) is identical to platelet-derived endothelial cell growth factor which is an angiogenic factor. We attempted to clarify the significance of dThdPase expression in esophageal squamous cell carcinoma (SCC).

METHODOLOGY

Tissues samples were taken from 50 patients with esophageal SCC after curative surgery. The expression of dThdPase was immunohistochemically examined using a monoclonal antibody to dThdPase (clone 654-1). Microvessels in SCC stained for Factor VIII-related antigen were counted. Vascular endothelial growth factor (VEGF) was immunostained with R11. Ki-67 antigen was immunostained with MIB-1, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate biotin nick end labeling was performed, and Ki-67 labeling index (LI) and apoptotic index were calculated.

RESULTS

The expression of dThdPase was observed in 30 patients (60%). Between the SCC with and without dThdPase expression, significant differences were found in microvessel count (p < 0.001) and VEGF expression (p < 0.01), but not in Ki-67 LI and apoptotic index. With regard to the clinicopathologic factors, significant differences were observed in histologic venous invasion (p < 0.01) and lymph node metastasis (p < 0.05). Survival rate after surgery was better in the patients with dThdPase-negative SCC (p < 0.05), and distant organ metastasis after surgery was frequently observed in the patients with dThdPase-positive SCC (p < 0.05).

CONCLUSIONS

These results suggest that dThdPase expression may be associated with angiogenic promotion and may be one of the prognostic factors in esophageal SCC.