PLK1 and breast cancer: Similarly, re-analysis of gene expression microarray data deposited in Gene Expression Omnibus Database (GEO-NCBI) from three independent studies using breast cancer cell lines (MCF7—accession number GSE55204, MDA-MB-231—accession number GSE25741 and BT-20—accession number GSE2222) revealed that FOXM1 silencing was not capable of altering both UBE2C and PLK1 gene expression (Supplementary Materials, Figure S1).