Neo-angiogenesis in locally advanced squamous cell head and neck cancer correlates with thymidine phosphorylase expression and p53 nuclear oncoprotein accumulation.

Thymidine phosphorylase (Th.P) is an angiogenic factor shown to induce endothelial cell migration and proliferation. On the other hand, loss of wild type p53 function leads to down-regulation of thrombospondin-1, an inhibitor of angiogenesis. In this immunohistochemical study we investigated the intratumoural angiogenesis and thymidine phosphorylase (Th.P) expression in paraffin-embedded bioptical material from 104 locally advanced squamous cell head and neck cancers. The nuclear accumulation of mutant p53 protein and the cytoplasmic expression of bcl-2 protein was also assessed. High vascular grade was observed in 56% and high Th.P tumour cell reactivity in 48% of cases. High microvessel score was associated with an increased percentage of cancer cells expressing thymidine phosphorylase (P = 0.001). Increased p53 nuclear accumulation also correlated with high vascular grade (P = 0.001). High histological grade and absence of bcl-2 overexpression were associated with lymph node involvement (P = 0.002 and P = 0.02 respectively). No correlation of clinically detected lymphadenopathy with angiogenesis and p53 was observed. We conclude that intense neo-angiogenesis in locally advanced squamous cell head neck cancer is a frequent event, which is associated with nuclear p53 accumulation and thymidine phosphorylase overexpression.