PTGS2 and cancer: Also, Asadollahi et al. demonstrated that the treatment of LS174T cancer cells and CRC mice model by a cocktail of 5 strains of Bifidobacteria has significant protective and anti-cancer effects via downregulation of effective genes such as EGFR, HER-2, and PTGS-2 (COX-2) and suggested as the most efficient treatment in CRC [20].