IFNG and neoplasm: Moreover, Th17 cells have been observed to be negatively correlated with TReg cells and positively correlated with effector immune cells including IFN-γ-secreting Th1 cells, cytotoxic CD8 T cells, and NK cells within the tumor microenvironment (Kryczek et al., 2009a; Zou and Restifo, 2010; Wilke et al., 2011).