STAT1 and obesity due to melanocortin 4 receptor deficiency: Compared to other liver disease etiologies, the NAFLD population has a much higher proportion of HCC in non-cirrhotic to cirrhotic livers.[16] Grohmann et al[18] suggested that obesity may cause NASH and HCC through different mechanisms, caused by a dissociation between the STAT-1 and STAT-3 activation pathways.