TP53 and colonic neoplasm: Densitometric analysis of colonic tumors of animals belonging to all groups showed that prior supplementation of both probiotics and celecoxib down-regulated the expression of K-ras significantly (p < 0.01) up-regulated the expression of wild type p53 in animals belonging to all treated groups but maximum effect was observed in L. rhamnosus GG + celecoxib+DMH (Group V) compared with counter controls and DMH-treated animals (Figs. 7 and 8).