GSTM1 and cancer: Three hypoxia alleviation strategies, including liposomal perfluorocarbon (PFC@lipo), liposomal hemoglobin (Hb@lipo), and PX-478, a commercial inhibitor for hypoxia-inducible factor-1α (HIF-1α, a hypoxia-activated transcription factor that encodes a variety of proteins responsible for cancer progression), have been compared and Hb@lipo has been identified to possess the best tolerance and safety and improve the effect of aPD-1 314.