MTOR and retinoblastoma: It has been reported that metformin and 5-aminoimidazole-4-carboxamide-1-β-4-ribofuranoside (AICAR), two AMPK agonists, inhibit the proliferation of retinoblastoma and prostate cancer cells via the AMPK/ACC and AMPK/mammalian target of rapamycin (mTOR) signaling pathways [16, 17].