PCNA and colonic neoplasm: Importantly, Khan R et al. found that oral GA could reduce the expression of Ki-67, NF-κB, proliferating cell nuclear antigen (PCNA), cyclooxygenase-2 (COX-2), and iNOS; and increase the levels of p53, connexin-43, Bcl-2, and caspase-3 proteins, thereby preventing the occurrence of 1,2-dimethylhydrazine-induced colon cancer [14,15].