PLK4 and breast cancer: In Gene Expression Profiling Interactive Analysis (GEPIA) dataset (num(T) = 104; num(N) = 28) of TCGA & GTEx database, Sanchez_Carbayo dataset (num(T) = 109; num(N) = 45) of the Oncomine database, and GSE 13507 dataset (num(T) = 188; num(N) = 67) of the GEO database, high PLK4 mRNA expression was detected in BC samples compared with that in normal bladder tissues (*P < 0.05, ***P < 0.001, Fig. 1A–C), suggesting PLK4 as an oncogene of BC occurrence.