LGR5 and gastric cancer: Liu et al. (2019) revealed that Tregs promoted Lgr5 expression in GC cells via TGF-β1 signaling pathway and was negatively associated with survival. Differences in the levels of the M1 macrophages were also observed. M1 macrophages are an integral cellular component of the immune system, and play a critical role in protection against intracellular pathogens and cancer cells (Yin et al., 2017). M1 macrophages have been reported to inhibit tumor growth in GC (Liu et al., 2013).