Recently, our group determined whether the BCR/ABL1 copy number, expression, and/or activity were responsible for telomere maintenance and the deregulated expression of selected shelterin components (TRF1, TRF2, RAP1, and POT1) in widely used chronic myeloid leukemia (CML) cell lines. Here, ABL1 is linked to chronic myelogenous leukemia, BCR-ABL1 positive.