GPR55 and neoplasm: Previous studies have demonstrated that GPR55 protein is present in the normal brain, gastrointestinal tract, spleen and adrenals (Sawzdargo et al. 1999; Ryberg et al. 2007; Oka et al. 2010) and its expression is increased in a number of tumours (Ford et al. 2010; Hu et al. 2011; Pineiro et al. 2011; Leyva-Illades and Demorrow 2013; He et al. 2015; Falasca and Ferro 2016).