Next, we found that MKI-2 decreased colony formation in MCF7 cells in response to irradiation (Figure 4F), with increased cleaved-PARP and phospho-Chk2 and decreased procaspase-2 (Figure 4G), which was more potent than AT13148 and MKI-1, suggesting that MKI-2 can enhance the radiosensitivity of breast cancer cells. The gene discussed is CHEK2; the disease is breast cancer.