Between 2012 and 2019, researchers developed and identified a set of FTO inhibitors, such as rhein, MO-I-500, meclofenamic acid (MA), fluorescein, 2-hydroxylglutarate (R-2HG), FB23, and FB23-2, that showed marked anti-tumor effects in vitro and in vivo (Table 2) [110–115]. This evidence concerns the gene FTO and neoplasm.