CDK4 and neoplasm: One of the cell cycle-related genes, CDK4/6 inhibitor palbociclib, was the first drug acceleratedly approved by the US FDA for breast cancer treatment and has shown promising effectiveness in various mouse tumor models, including glioblastoma.[4] However, despite the significant results observed in experiments with cell cycle inhibitors, their performance in clinical trials for glioblastoma has been suboptimal due to the lack of specific markers and cytotoxicity issues.[5–9] Consequently, the quest for new cell cycle-related molecular markers for glioblastoma continues.