GSTM1 and neoplasm: Determination of blood oxygen saturation (StO2=HbO2/THb) and total hemoglobin concentration (THb=HbO2+Hb) is the most common application of diffuse optical methods [30] The obtained StO2 values are used to assess tissue hypoxia [37] and tumor angiogenesis [41] DOS is used to monitor StO2 in tumor tissues during chemotherapy [8], radiation therapy [11], and photodynamic therapy [42]