Published online Jun 24, 2021. doi: 10.5306/wjco.v12.i6.429
Peer-review started: October 22, 2020
First decision: December 3, 2020
Revised: December 30, 2021
Accepted: April 8, 2021
Article in press: April 8, 2021
Published online: June 24, 2021
Processing time: 241 Days and 17.5 Hours
Therapeutic manipulation of the immune system in cancer has been an extensive area of research in the field of oncoimmunology. Immunosuppression regulates antitumour immune responses. An immunosuppressive enzyme, indoleamine 2,3-dioxygenase (IDO) mediates tumour immune escape in various malignancies including breast cancer. IDO upregulation in breast cancer cells may lead to the recruitment of regulatory T (T-regs) cells into the tumour microenvironment, thus inhibiting local immune responses and promoting metastasis. Immunosuppression induced by myeloid derived suppressor cells activated in an IDO-dependent manner may enhance the possibility of immune evasion in breast cancer. IDO overexpression has independent prognostic significance in a subtype of breast cancer of emerging interest, basal-like breast carcinoma. IDO inhibitors as adjuvant therapeutic agents may have clinical implications in breast cancer. This review proposes future prospects of IDO not only as a therapeutic target but also as a valuable prognostic marker for breast cancer.
Core Tip: Indoleamine 2,3-dioxygenase might be utilized as a potential biomarker and immunotherapeutic target in breast cancer patients.