IGF1 and Lassa fever: Research has shown that mTORC1 pathway is closely linked to LF fibrosis.[66] Mechanical stress promotes the production of insulin-like growth factor-1 (IGF-1) by LF cells, which in turn promotes the synthesis of type 1/3 collagen (COL-1/3) through the IGF-1R/Akt/mTORC1 pathway.