In order to evaluate the potential of CtBP to be breast tumor therapeutic target, the cell viability was measured and we observed that MTOB was able to induce significant decrease of cell viability, which is consistent with Straza's observation in HCT116 cells.33 However, adding extra NaHCO3 together with MTOB significantly rescued the cell viability (Figure 5h and Supplementary Figure 4G), suggesting that pH homeostasis disturbance significantly contributes to MTOB-induced cell apoptosis. Here, CTBP1 is linked to breast neoplasm.