The results we obtained for CXCL1 are puzzling, as the concentrations by themselves showed no differences between the study groups; however, when analyzing diagnostic features, the inclusion of CXCL1 in the combined analysis decreased the level of specificity and both predictive values, while increasing the sensitivity of the test and significantly improving the quality of the test, especially in the luminal A subgroup of BC, whereas, in ROC analysis, CXCL8 showed no such effect. The gene discussed is CXCL8; the disease is breast cancer.