As Hb is the main molecule carrying oxygen in the body, a decrease in Hb concentration increases the number of hypoxic cells in the body, and the sensitivity of tumor cells to radiation and chemotherapy decreases under hypoxic conditions.36 Hypoxia can induce the formation of tumor cells with an invasive phenotype, leading to tumor progression and chemotherapy resistance.37 Moreover, hypoxia can also stimulate tumor neovascularization by activating multiple cell signaling pathways, thereby accelerating tumor invasion and metastasis.38, 39. The gene discussed is GSTM1; the disease is neoplasm.