COX-2 expression correlates with microvessel density in non-melanoma skin cancer from renal transplant recipients and immunocompetent individuals

Angiogenesis, the generation of a new vascular network, is regulated in part by inducers of endothelial cell migration and proliferation, such as cyclooxygenase-2 (COX-2). Microvessel density (MVD) measurement is widely used to quantify angiogenesis in tissue sections of tumors, including cutaneous malignancies. The increasing number of successful renal transplantations worldwide is producing a progressive increase in patients at risk for non-melanoma skin cancers, such as squamous cell carcinoma (SCC), basal cell carcinoma (BCC), and Bowen's disease (BD), and at significantly increased risk for metastatic SCC. The aim of this study was to investigate whether there was any difference in angiogenesis between these tumor types in renal transplant recipients (RTRs) and immunocompetent individuals (ICIs) and whether angiogenesis in these tumors was related to COX-2 expression. The study measured angiogenesis and COX-2 expression in BD, SCC, BCC, and normal skin from both RTRs and ICIs. Vessel counts were performed, and COX-2 immunoexpression was assessed semiquantitatively. The MVD counts differed significantly between normal skin and all tumor types. Significant differences in MVD density were found between all SCCs and BCCs. BCCs from RTRs had significantly greater MVD at the invasive front of the tumor than BCCs from ICIs. Increased COX-2 expression correlated with increased MVD in all tumors examined. These findings indicate a difference in vascular profiles between RTRs and ICIs in BCCs and suggest a relationship between COX-2 and angiogenesis that may provide a possible treatment target for skin tumors in these 2 patient populations.