We characterized these Pol γ inhibitor molecules in vitro and in vivo, and present 3,3’-[(1,1’-Biphenyl)-4’,4’-diyl)bis(azo)]bis[4-amino-1-naphthalenesulfonic acid] (congo red; CR; Zinc 03830554) that is a sulfonated diazo dye as a high affinity binder and inhibitor of the Pol γ enzyme with specific cytotoxicity against MLH1 deficient colon cancer cells and tumors. Here, MLH1 is linked to malignant colon neoplasm.