PTGS2 and neoplasm: Analysis of CD8+ T cells (red), with co-localization of cleaved caspase-3 (green) revealed that the tumor density of CD8+ T cells undergoing apoptosis, measured as the percent of CD8+ cells that are cleaved caspase-3+, was significantly higher in the COX2-overexpressing TM40D-COX2 group compared to the TM40D tumors (Figure 5C, p<0.01).