PTGS2 and skin neoplasm: Overall, a high COX-2 expression revealed a statistically significant correlation with Ki-67 (p = 0.03), however when oral and skin melanomas were analysed independently only the skin tumours presented statistical significance (p = 0.01) (representative images of Ki-67, melan-A, PNL-2 and COX-2 staining are shown in Figure 1).