HIF1A and colorectal cancer: Tang et al. [31] reported that hypoxia-inducible factor-1α (HIF-1α) and TGF-β2 were secreted by cancer-associated fibroblasts which promoted the strong expression of glioma-associated oncogene protein-2 in cancer stem cells; this protein is related to the chemoresistance to the combination of 5-fluorouracil and oxaliplatin and relapse of colorectal cancer following chemotherapeutic strategies.