BCR and chronic myelogenous leukemia, BCR-ABL1 positive: One-fifth of all adult leukaemia cases are caused by CML [1], which is in turn caused by the Philadelphia chromosome, i.e., the reciprocal translocation of chromosomes 9 and 22, t(9; 22)(q34; q11.2), leading to BCR::ABL1 tyrosine kinase [2].