Relaxin/RXFP1‐mediated cancer growth and invasion have been reported in breast, thyroid, prostate, and other cancer models (Bigazzi, Brandi, Bani, & Sacchi, 1992; Binder, Hagemann, Husen, Schulz, & Einspanier, 2002; Feng et al., 2007; Hombach‐Klonisch et al., 2006; Hombach‐Klonisch, Buchmann, Sarun, Fischer, & Klonisch, 2000; Tashima, Mazoujian, & Bryant‐Greenwood, 1994; Vinall et al., 2011). The gene discussed is RXFP1; the disease is cancer.