According to Qian et al. [51], in AML, PTGDR2 (referred to as GPR44 in the article) inhibited the KRAS-mediated MAPK and PI3K/AKT/mTOR signaling pathways, which promoted apoptosis of leukemia-initiating stem cells, whereas, PTGDR2 knockdown enhanced colony stimulation. This evidence concerns the gene PTGDR2 and acute myeloid leukemia.