PTGS2 and colorectal adenoma: Comparison of the immunoexpression of the p53, COX-2, and caspase-3 proteins between the colorectal adenomas and the non-neoplastic mucosa yielded a significant difference (p<0.0001) in the immunoexpression of p53 between GA and GC, whereas the expression of COX-2 (p=0.14) and caspase-3 (p=0.24) did not exhibit a significant difference (Table 1).