Angiogenesis in invasive squamous cell carcinoma of the lip: tumor vascularity is not an indicator of metastatic risk

BACKGROUND: Recent studies have shown that tumor growth beyond a certain size requires angiogenesis. Microvessel density has, moreover, correlated with metastatic risk in some tumors. Invasive squamous carcinoma (SCC) can develop in the epithelium of the lip and metastasize even when relatively small. This study investigates neovascularization and its relationship to metastatic risk in this tumor. METHODS: All 41 primary SCCs of the lip diagnosed at our institution from 1960 to 1991 were immunostained for factor VIII. Microvessel grade (Mv) from 1+ to 4+ and the average number of vessel profiles (TMvD) in the highest density 200 x (0.785 mm2) and 400 x (0.196 mm2) microscopic fields were determined. TMvDs were compared with those of adjacent non-tumor tissue (NTMvD). Normalized counts (TMvDns) were calculated as TMvD/NTMvD. TMvDs and TMvDns of metastasizing (N = 10) and non-metastasizing (N = 31) tumors were compared (student t-test). RESULTS: In all SCCs TMvDs exceeded NTMvDs (50 vs. 35 at 200 x, P = 0.0014, and 26 vs. 14 at 400 x, P < 0.0001). Metastasizing and non-metastasizing tumors did not, however, differ in Mv, TMvD, or TMvDn. CONCLUSIONS: Angiogenesis develops, but is not quantitatively related to metastatic risk, in primary invasive squamous cell carcinoma of the lip.