In one study, Basu and Haldar indicated that overexpression of P53 in some cancer cells via reducing the bcl-2 protein expression leading to in apoptotic cell death.45 In another study, Brassat et al reported that telomerase inhibition in CML patient is highly dependent on the presence of functional p53.46 These results are consistent with the results of the current study that overexpression of P53 is associated with decreasing telomeric length and telomerase activity. This evidence concerns the gene BCL2 and chronic myelogenous leukemia, BCR-ABL1 positive.