To establish the clinical relevance of tumour proteasomal deubiquitinases expression in CML patients, the expression of proteasomal deubiquitinases (USP14, UCHL5 and POH1) was examined in peripheral blood mononuclear cells (PBMCs) from CML patients as well as that from healthy donors. This evidence concerns the gene UCHL5 and chronic myelogenous leukemia, BCR-ABL1 positive.