HCST and cancer: A number of G2 genes are key regulators of the basal-like tumorigenesis, such as CXCR6, HCST, C3AR1, GBP4, LY96, ANKRD22, FPR3 and FCGR2A. These genes show the highest betweenness centrality and node degree among tumours, and appeared over-expressed in Basal I. In other reports, the CXCR6 over-expression has been linked to TNBCs, with distinct roles in autoimmunity and cancer [56].