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World J Clin Oncol. Jun 24, 2021; 12(6): 429-436
Published online Jun 24, 2021. doi: 10.5306/wjco.v12.i6.429
Review of 10 years of research on breast cancer patients: Focus on indoleamine 2,3-dioxygenase
Kashif Asghar, Asim Farooq, Bilal Zulfiqar, Asif Loya
Kashif Asghar, Department of Basic Sciences Research, Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore 54000, Pakistan
Asim Farooq, Department of Clinical Research, Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore 54000, Pakistan
Bilal Zulfiqar, Griffith Institute for Drug Discovery, Griffith University, Brisbane, Queensland 4111, Australia
Asif Loya, Department of Pathology, Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore 54000, Pakistan
Author contributions: Asghar K generated the idea and drafted the manuscript; Farooq A, Zulfiqar B were involved in acquisition of the data and contributed in manuscript writing; Loya A critically revised the manuscript for important intellectual content; each author has approved the final version of the manuscript before publication.
Conflict-of-interest statement: Authors declare no conflict of interests for this manuscript.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Kashif Asghar, DVM, PhD, Research Scientist, Department of Basic Sciences Research, Shaukat Khanum Memorial Cancer Hospital and Research Centre 7A, Block R3, Johar Town, Lahore, Punjab 54000, Pakistan. drkashifasghar@gmail.com
Received: October 22, 2020
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
Abstract

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.

Keywords: Indoleamine 2,3-dioxygenase; Breast cancer; Therapeutic target; Prognostic marker; Immune responses; Immune escape

Core Tip: Indoleamine 2,3-dioxygenase might be utilized as a potential biomarker and immunotherapeutic target in breast cancer patients.