IDO1 and neoplasm: Previously, single reports have suggested potential biomarkers to be possibly associated with clinical activity, like forkhead box P3 and IDO, a post-treatment increase in tumor-infiltrating lymphocytes [50] and expression of immune-related genes like TH1 associated cytokines (CCL4, CCL5, CXCL9, 10) as well as markers for CD8 + cytotoxic T cells (i.e., Perforin1 and Granzyme B) [50,51].