B2M and chronic myelogenous leukemia, BCR-ABL1 positive: The expression level of the TCRζ, FcεRIγ, ASF/SF-2, ZAP-70 genes was determined by real-time PCR using the SYBR Green I technique and quantitatively assessed by comparison with the β2M reference gene using cDNA from PBMCs collected from CML, CML-CR and healthy control samples.