Ph1-negative chronic myelocytic leukemia (CML) with an unusual karyotype☆

Abstract A case of Ph 1 -negative chronic myelocytic leukemia is reported. Cytogenetic analysis and the development of colonies in soft agar culture 2 months before the clinical manifestation of the acute phase of the disease clearly indicated the bad prognosis of the patient. An extra #8 chromosome was found in 23% of his cells. Also of note was the presence of an abnormal clone characterized by t(12;13).