Deletions or translocations involving chromosomal band 13q14, the locus of the retinoblastoma (RB1) gene, are observed in a variety of hematological malignancies including myelofibrosis (MF), MDS, AML, chronic myelogenous leukemia (CML) and chronic lymphocytic leukemia (CLL) [4]. This evidence concerns the gene RB1 and chronic myelogenous leukemia, BCR-ABL1 positive.