The UALCAN analysis showed that only CXCL12 (Fig. 5B) had a lower expression level in basal-like (triple-negative) breast cancer compared with luminal-like breast cancer, while CXCL5 (Fig. 5A), IDO1 (Fig. 5C), MIF (Fig. 5D), PTGS2 (Fig. 5E), and VEGFA (Fig. 5F) all had increased expression levels in basal-like breast cancer. This evidence concerns the gene IDO1 and breast cancer.