Cancer cells can also signal to the immune predators in the tumor through expression of immune checkpoints on the cancer cells, such as PD-L1 and CTLA4 (Pardoll, 2012), or through secretion of soluble immunosuppressive factors, such as TGF-β (Wojtowicz-Praga, 2003), IL-10 (Kim et al., 2006), and soluble WNTs (Liang et al., 2014; Sun et al., 2017). This evidence concerns the gene CTLA4 and cancer.