Considering the restoration of PTPRG expression in CML patients who reach the MMR (major molecular response) after TKI-treatment, as opposed to those who have not reached the MMR, can make the PTPRG a “tool” to monitor the recovery of normal hematopoiesis (Della Peruta et al., 2010; Vezzalini et al., 2017; Drube et al., 2018; Ismail et al., 2021). This evidence concerns the gene PTPRG and chronic myelogenous leukemia, BCR-ABL1 positive.