For example, Feng et al. [14] found that upregulated piRNA-823 in colorectal cancer cells could inhibit the ubiquitination of hypoxia-inducible factor-1 (HIF-1) by increasing the expression of glucose-6-phosphate dehydrogenase (G6PD), and this inhibition increases glucose consumption in cancer cells and reduces the intracellular reactive oxygen species content. The gene discussed is G6PD; the disease is colorectal cancer.