INSR and Insulin resistance: IGF-1 is a more powerful growth factor than insulin that can also bind to insulin receptors and can stimulate the RAS-RAF-MEK-ERK or the PI3K/AKT/mammalian target of rapamycin (mTOR) pathways while also inhibiting the antiapoptotic phosphatase and tensin homolog (PTEN).[12] A study examining the role of tumor necrosis factor (TNF)-alpha in insulin resistance demonstrated that the insulin signaling and apoptosis pathways are intimately connected through PTEN phosphatase, TNF-alpha, and insulin.[13] PTEN inhibits PI3K signaling of the insulin pathway producing insulin resistance.