CCNE1 and breast cancer: In addition, analyzing GE data from BC cell lines of the Iorio et al. dataset,20 but taking into account the IC50 values for palbociclib obtained from a previous BC-focused study,19 we were able to demonstrate that CCNE1, RB1, and CCNE1 /RB1 ratio correlated with higher IC50 also in BC cell lines (Fig. 5a dark gray bars, minimum |R| >0.45, maximum FDR = 0.01, correlation test).