Therefore based on our hypothesis the objectives of this study were (i) To investigate the expression of Notch receptors in CD34+ primary CML at mRNA and protein level, (ii) To investigate the expression of Notch target genes Hes1 and Herp1&2 using PCR to determine the activity of Notch signalling in CD34+ primary CML cells, (iii) To investigate the possible cross-talk between Notch and BCR-ABL in primary CD34+ CML cells as well as in cell line models, and lastly (iv) To validate the Notch-BCR-ABL relationship using CML microarray datasets from GSE database. This evidence concerns the gene ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive.