UBE2O, an E2 ubiquitin-conjugating enzyme, plays a tumor-promoting role in multiple solid tumors, including breast cancer, prostate cancer, hepatocellular carcinoma (HCC), and non-small cell lung cancer (NSCLC), by driving tumor progression [16,20,21,22,23,24,25,26]. The gene discussed is UBE2E2; the disease is hepatocellular carcinoma.