STAT3 and obesity due to melanocortin 4 receptor deficiency: Through a series of detailed experiments, Grohmann et al.[122] demonstrate that while obesity promotes NASH pathogenesis through STAT-1 (signal transducer and activator of transcription 1) activation, NASH-associated HCC is mostly driven by STAT-3 (signal transducer and activator of transcription 3), a transcription factor implicated in the immune system.