CDK4 and breast neoplasm: Our previous report on the incidence of CDK4 overexpression/gene amplification in pancreatic NETs, combined with the response of PNET cell lines to CDK4/CDK6 inhibitors particularly in combination with mTOR inhibitors29, helped lead to multiple ongoing clinical trials for neuroendocrine and breast tumors (ClinicalTrials.gov Identifiers NCT02420691, NCT03070301, and NCT02732119).