CDK4 and cancer: Constitutive activation or inhibition, whether caused by mutations or other methods, can result in dysregulated signal cascades, which can lead to cancer and other diseases.35,36 The tyrosine kinase inhibitors inhibit this dysregulated signal cascade and block transcription in both genetic amplification and mutation, leading to the disease-causing signals.36 The compounds 47–51 showed excellent activity against various kinases, including TKs, PI3K, and CDK4/6.