Thus, we looked at Hemoxigenase‐1 transcription at 6 hours of PTL or DMAPT treatment by q‐PCR and observed that all CML cell lines (K562, MEG01, KCL‐22 and Kasumi‐4) showed up‐regulation of HMOX‐1 transcription, the effect was significantly higher in CD34+lin− CML‐CP samples. This evidence concerns the gene HMOX1 and chronic myelogenous leukemia, BCR-ABL1 positive.