Indeed, two clinical studies in this review that assessed both in vitro and in vivo levels of ghrelin in patients with cancer reported that despite findings of high ghrelin expression in tumor tissue, plasma ghrelin measures were either similar to those of healthy controls (Ekeblad et al. 2007) or within the reference range for this measure (Tsolakis et al. 2008). This evidence concerns the gene GHRL and cancer.