IDO1 and prostate cancer: Recent studies show a strong link between the substantial presence of CD8 + T-cells and extended survival in clear cell renal cell carcinoma and prostate cancer.[14] Furthermore, NK cells can be activated to recognize and kill tumor cells through a set of stimulatory and inhibitory receptors, thus potentially amplifying immune responses.[22] The observed inverse relationship between IDO1 expression and NK cells in cervical cancer could be a significant factor in the integrated approach to treating cervical cancer.