IDO1 and neoplasm: We and others, have reported on various factors mediating tumor immune suppression such as high expression of HLA- E coupled with lower infiltration of CD8+ T cells and NK cells (8, 9), reduced HLA class I expression (10), reduced infiltration of M1 type macrophages (11), increased PDL-1 expression on both tumor cells and myeloid cells (7, 12), increased Indoleamine-2,3-dioxygenase (IDO) metabolic activity (13) and reduced major histocompatibility complex class I chain-related molecule A (MICA) expression (14) aiding immune escape by cervical cancer.