GSTM1 and thalassemia: Moreover, compared with individuals with non-β0/β0 thalassemia, β0/β0 individuals generally require higher VCN of the therapeutic vector to achieve curative levels of Hb, which increases the risk of oncogenicity due to insertional mutagenesis (Thompson et al., 2018; U.S. National Library of Medicine, ; Breda et al., 2012).