Red cluster investigations, also positioned as a basic theme, designate FGF21 as a crucial hepatokine, exhibiting hepatic mRNA expression that is 9 times elevated in MASLD patients, while phase 2 trials reveal that pegozafermin analogs diminish hepatic fat by 45% through PPARα activation [47,48]. The gene discussed is FGF21; the disease is metabolic dysfunction-associated steatotic liver disease.