HIF1A and neoplasm: The patients in cluster B had the worst prognosis (OS and PFS), compared to patients in cluster A. Moreover, we also found cluster B featured high-level activation of the HIF-1 pathway, angiogenesis process, and glycolysis process; however, opposite characteristics were seen in cluster A. This phenomenon indicated that cluster B had a more obvious hypoxia status than cluster A. Tumor hypoxia induces HIF-1 overexpression to regulate a string of biological processes (27).