SLC25A18 and neoplasm: Finally and strikingly, the existing seven MGCs—ANF-RGC, CNP-RGC, STa-RGC, ROS-GC1, ROS-GC2, ONE-GC, GC-GC—in a specific fashion, by synthesizing cellular second messenger cyclic GMP, are linked with the physiological processes of blood pressure regulation, cellular growth, sensory transductions, neural plasticity, memory, temperature sensing (reviewed in Sharma et al., 2016) and, with tumor suppression (reviewed in Steinbrecher and Cohen, 2011; Windham and Tinsley, 2015).