Because (1) S. cerevisiae or WGP might attenuate colon cancer through a direct effect on immune cells [10] or tumor cells [1,11,18], (2) the presence of Dectin-1 (a major receptor of WGP) in macrophages and its importance on cancer cells are well-known [19], and (3) there remains a lack of data on AOM-induced cancer in cGAS-/- mice, we hypothesized that the beta-glucan of S. cerevisiae (WGP) attenuated cancer, even with the more cancer-susceptible property of cGAS-/- mice, through the induction of tumoricidal macrophages and tested the hypothesis in vivo and in vitro. The gene discussed is CGAS; the disease is cancer.