The KIF2C gene has been demonstrated to be regulated by EZH2, the catalytic subunit of the PRC2, in the context of melanoma, which supports our findings of a link between the CBX2, a member of the PRC1 complex, and KIF2C expression.32 These analyses demonstrate that two out of the five genes identified to be overexpressed in a subset of patient tumours may alter the breast cancer transcriptome in a biologically plausible manner. This evidence concerns the gene PRC1 and breast cancer.