In particular, CDK4/6 inhibitors were significantly associated with grade ≥3 AEs, such as neutropenia, anemia, leukopenia, thrombocytopenia, alanine aminotransferase (ALT), aspartate aminotransferase (AST), nausea, headache, and back pain (Table 3). This evidence concerns the gene CDK4 and Thrombocytopenia.