For example, (1) tumor cell-macrophage close proximity (rather than direct contact) may be required so that an increased macrophage Gpr132 expression can better sense a gradient of the signal sent from tumor cells - this is supported by previous studies indicating Gpr132 as a pH and lipid sensor that may regulate immune cell trafficking (Justus et al., 2013; Vangaveti et al., 2010); (2) upon activation by tumor signals, macrophage Gpr132 may modulate macrophage intracellular signaling and downstream targets, which in turn promotes cancer cell proliferation (Figure 5Q). Here, GPR132 is linked to cancer.