Nastran Hashemzadeh
1,2, Khosro Adibkia
1,3 
, Jaleh Barar
1,3* 1 Research Center for Pharmaceutical Nanotechnology, Biomedicine Institute, Tabriz University of Medical Sciences, Tabriz, Iran
2 Students' Research Committee, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
3 Department of Pharmaceutics, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
Abstract
Trafficking of macromolecular immunotherapy agent into the tumor microenvironment (TME) is a
challenging issue. In the TME, cancer cells exploit indoleamine 2, 3-dioxygenase (IDO), as a cytosolic
enzyme that catalyzes the L-tryptophan (Trp) through the kynurenine (Kyn) pathway, which could
negatively regulate the activity of T cells. Thus, Trp/Kyn pathway, can be targeted with novel treatment
modalities such as IDO1 inhibitor to benefit patients with aggressive solid tumors.