CDK7 and breast cancer: A preclinical study demonstrated that CDK7 inhibitors, such as THZ1, significantly suppressed the growth of resistant HER2-positive breast cancer cells (SKBR3, BT474, MDAMB453, HCC1954, HCC1569 and MDAMB361, average IC50 = 60 nM), and reduced phosphorylation of RNA polymerase II, thereby impairing cell transcriptional activity and enhancing apoptosis (Sun et al., 2020).