Vascular endothelial growth factor, wild-type p53, and angiogenesis in early operable non-small cell lung cancer.
Giatromanolaki A., Koukourakis MI., Kakolyris S., Turley H., O'Byrne K., Scott PA., Pezzella F., Georgoulias V., Harris AL., Gatter KC.
Vascular endothelial growth factor (VEGF) is a cytokine that is involved in tumor angiogenesis. Wild-type p53 (wt-p53) protein has been shown in cell lines to suppress angiogenesis through thrombospondin regulation. In this study, we immunohistochemically examined the expression of VEGF, nuclear and wild-type cytoplasmic p53, bcl-2, epidermal growth factor receptor, and c-erbB-2 oncoprotein; vascular grade; proliferation index; and extent of necrosis in non-small cell lung cancer (NSCLC). We analyzed 120 cases of early-stage NSCLCs (81 squamous cell carcinomas and 39 adenocarcinomas) treated with surgery alone (median follow-up, 63 months; range, 45-74 months). VEGF expression showed a positive association with high vascular grade (microvessel score of >75 per x250 field; P = 0.008), although about half of the LVG cases also expressed VEGF. None of the p53 antibodies examined correlated with angiogenesis. However, wt-p53 expression was inversely associated with VEGF expression, suggesting that wt-p53 is involved in the suppression of the VEGF gene. Combined analysis of VEGF, wt-p53, and microvessel counting showed that, although wt-p53 loss associates with VEGF switch-on, p53 protein may not be involved in the regulation of the angiogenic events downstream of VEGF expression. Moreover, no significant association of bcl-2 and c-erbB-2 oncoprotein expression with VEGF expression was observed. T/N stage, grade, Ki67 proliferation index, and extent of necrosis were not correlated with VEGF expression. Survival analysis showed that VEGF correlated with poor survival (P = 0.04) and was significant in node-negative cases (P = 0.03). We conclude that VEGF is an important angiogenic factor in NSCLC, its expression being dependent on wt-p53 loss.