CXCL9 and breast cancer: Moreover, in the subgroup analysis of molecular subtypes using the UALCAN database, we found that both the mRNA and protein levels of CXCL9 in the TNBC subtype were markedly higher than those in the luminal subtype of BC (Figures 2B, C, P<0.01; Supplementary Tables S1, S2, P<0.01).