Chen and colleagues have reported the expression of IDO1, estrogen receptor (ER), progesterone receptor (PR), human epithelial receptor 2, cytokeratin 5/6, epithelial growth factor receptor, phosphorylated AKT, neoangiogenesis, nitrogen oxide synthetase 2 (NOS2), cyclooxygenase 2 (COX2), FoxP3, CD8+ and CD11b molecules on archival breast cancer tissue [104]. Here, PTGS2 is linked to breast cancer.