In addition to the evidence that exposure to NMs (such as Si-NPs and CNTs) induces activation of these signals (MAPK, TGF-β and HIF1-α) [6, 56, 88, 110], we speculate that P53 mutation may be involved in NM-induced liver cancer progression by activating MAPK, TGF-β and HIF1-α signaling. The gene discussed is HIF1A; the disease is liver cancer.