ESR1 and breast cancer: A few works showed that higher CXCL8 concentrations were present in patients with ER- breast cancer than ER+ types (p < 0.0001 [67]; p = 0.012 [52]), HER2+ breast cancer type compared to HER2- (p < 0.001 [67]), and the TNBC subtype compared to non-TNBC (p = 0.001 [68]), but showed no difference in concentration for the PR receptor [67].