AZD1390, belonging to the same potent series as AZD0156, is an exquisitely potent, highly selective, and orally bioavailable ATM inhibitor.1256 AZD1390 effectively sensitizes the brain metastasis of breast cancers with DDR mutation to radiation therapy.1257 Multiple clinical trials of AZD1390 for cancer treatment are ongoing. Here, ATM is linked to breast cancer.