CDK4 and neutropenia: In the subgroup analysis of different CDK4/6 inhibitors (Figure S2), the incidences of grade 3-4 neutropenia were significantly higher in patients receiving ribociclib-based regimen (RR=47.33, 95% CI=9.67-231.61), and palbociclib-based regimen (RR=68.15, 95%CI=17.09-271.83).