GSTM1 and cancer: The use of hemoglobin (Hb)-based oxygen (O2) carriers (HBOCs) as a cancer chemosensitizing agent has been studied for a variety of prior generation HBOCs including crosslinked Hb (XLHb) [1–4],polymerized Hb (PolyHb) [5–12], surface conjugated Hb [13–16], and liposome encapsulated Hb [17–20].