CDK4 and neoplasm: These include evaluating the therapeutic effects of CDK4/6 (cyclin-dependent kinase 4/6) inhibitors combined with endocrine therapy168 and testing the regulatory and anti-tumor effects of DOT1L (disruptor of telomeric silencing-1-like) inhibitors on triple-negative breast cancer stem cells in triple-negative breast cancer PDX and PDX-derived organoid.169