Fig 1E shows TCGA analysis comparing breast cancer subtypes and confirms that CXCR4 expression is highest and GRK3 is lowest in basal types, though these trends are seen in all the tumor subtypes to some degree. GRK5 expression is again shown to be downregulated the most in luminal B subtype, but could also be important in other types, including basal tumors. Taken together, there is potential clinical significance for decreased GRK3 expression in human basal breast cancer that could indicate metastatic potential. Here, CXCR4 is linked to breast cancer.