TP53 and cancer: Since we detected p53-dependent up-regulation of Mdm-2 expression (Table 1) in HCT116p53+/+ cells, and Mdm-2 was shown to bind FAK to down-regulate p53, providing survival to cancer cells [11], we used compound M13 that disrupted interaction of FAK and Mdm-2, called M13 that up-regulated p53 activity and caused apoptosis in HCT116 p53+/+ cells [14] in combination with R2 in clonogenicity assay to test if combination of R2 and M13 will decrease cancer cell clonogenicity more effectively than each agent alone.