Specifically, HIF-1/2α promotes glucose uptake in tumor cells, acidification of the tumor environment, and the formation of new blood vessels by upregulating genes such as GLUT1, CA9, and VEGF, and supports tumor growth (Zh et al., 2023; Almanzar et al., 2025; Reinfeld et al., 2022). This evidence concerns the gene CA9 and neoplasm.