IL1B and obesity due to melanocortin 4 receptor deficiency: By combining both autochthonous GEMMs and syngeneic transplant models, the Jain group demonstrated that obesity (HFD and Lepob/ob induced) enhances PDAC-associated desmoplasia via increased PSC activation by tumor-associated neutrophils (TANs) recruited by adipose-derived IL1β (Incio et al, 2016a).