TERF1 and chronic myelogenous leukemia, BCR-ABL1 positive: 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.