Additionally, studies on gastrointestinal stromal tumor (GIST) cell lines with intact RB revealed that the dual inhibition of CDK2 (PF-06873600, CDK2 inhibitor II) and CDK4/6 (palbociclib or abemaciclib) effectively arrested cells in the G1 phase [67]. Here, CDK4 is linked to gastrointestinal stromal tumor.