PTGS2 and breast neoplasm: In parallel, inhibition of CXCL8 or of CXCR1/2 has increased the sensitivity of breast tumor cells to chemotherapeutic drugs, accompanied by reduced proportion of CSCs, angiogenesis, tumor growth and/or metastasis, with roles attributed to cyclooxygenase 2 (COX-2) in this process (103, 104, 110, 113, 121, 122).