Al-Achkar and co-workers however, concluded that GSTM1 null genotype was associated with increase risk of CML: (OR=2.55; 95% CI; 1.54-4.22; p-value = 0.0002) (Al-Achkar et al., 2014). Here, GSTM1 is linked to chronic myelogenous leukemia, BCR-ABL1 positive.