P3H3 and gastric cancer: The expression of microRNA (miR)-301a-3p by gastric cancer exosomes in an HIF-1α-dependent manner, results in its transmission between gastric cancer cells via exosomes to inhibit HIF-1α degradation by targeting prolyl hydroxylase 3 (PHD3), an essential hypoxia regulator capable of hydroxylating HIF-1α subunits to ubiquitinate degradation.