CDK7 and breast cancer: Moreover, some CDK7 inhibitors have entered Phase I clinical trials for breast cancers.33,34 In the context of HNSCC, elevated levels of CDK7 have been associated with poor clinical outcomes.41,42 On this basis, CDK7 has been suggested as a potential therapeutic target for HNSCC; however, this possibility has not yet been explored in preclinical and/or clinical settings.