HGF and obesity due to melanocortin 4 receptor deficiency: Several studies have also demonstrated that serum HGF elevation has been identified in patients with varying types of disorders, such as obesity, metabolic syndrome, diabetes mellitus, multiple myeloma, gastric cancer, and bladder cancer, indicating that HGF levels were associated with disease progression (Oliveira et al., 2018; Wang et al., 2007; Corcoran et al., 2013; Sugimura et al., 1997).