Chromobox protein homolog 2 (CBX2) is a polycomb protein, responsible for polycomb-repressive complex 1 (PRC1) targeting to chromatin via recognition of the repressive mark H3K27me3 []. CBX2 is required during sex determination to stabilize the testis fate by blocking the upregulation of bivalent ovary pathway genes []. It is overexpressed in breast cancer and plays an essential role in tumour progression [, ].
