PLK1 and breast cancer: In clinical breast cancer data sets (https://bcgenex.ico.unicancer.fr/BC-GEM/GEM-Accueil.php?js=1)23,24, PLK1 mRNA overexpression was more common in Luminal B ER+ BCs than in Luminal A ER+ BCs (Supplementary Fig. 12E), high-risk Nottingham prognostic index (NPI) (Supplementary Fig. 12F), and significantly associated with poor survival in the whole cohort (p < 0.0001) (Supplementary Fig. 12G) and ER+ cohort (p < 0.0001) (Fig. 6J) but not in the ER- cohort (p = 0.25) (Supplementary Fig. 12H).