GSTM1 and neoplasm: This impact results from three related key points: (1) the hemoglobin (Hb) level was shown to strongly correlate with tumor oxygenation in numerous cancers [9], (2) substantial data show that tumor hypoxia is involved in processes conferring a growth advantage and the development of a more malignant phenotype [10-15], and (3) hypoxic tumors are reported to be less sensitive to ionizing radiation since the production of free radicals, which are responsible for lethal DNA breaks, increases with the O2 partial pressure (pO2) [16-18].