Novel variant translocation t(9;22;11)(q34;q11.2;p15)inv(9)(p13q34) in chronic myeloid leukemia involving a one-step mechanism

BELLI, CAROLINA; ALÚ, MARÍA FERNANDA; ALFONSO, GRACIELA; BIANCHINI, MICHELE; LARRIPA, IRENE

CYTOGENETIC AND GENOME RESEARCH

KARGER

Año: 2011 vol. 132 p. 304 - 308

1424-8581

Chronic myeloid leukemia (CML) is a clonal malignant disorder of a pluripotent hematopoietic stem cell characterized by the presence of a Philadelphia (Ph) chromosome. Less than 10% of patients present variant Ph chromosomes involving 1 or more additional chromosomes, other than chromosomes 9 and 22, with uncertain prognosis. There are mainly 1- or 2-step mechanisms proposed to explain the genesis of variant Ph chromosomes depending on whether the involved chromosomes are simultaneously broken and rejoined or if a standard t(9; 22) occurs first. By combined standard cytogenetic and FISH analysis we detected a novel variant Ph translocation among chromosomes 9, 11 and 22 in a patient with CML without progression to an accelerated phase of the disease after 7 years, with the derivative chromosome 9 also having an acquired pericentric inversion. This novel case illustrates the use of FISH in metaphase to confirm a new rearrangement not previously described in variant Ph formation and that the present karyotype could have originated by a 1-step mechanism with 4 simultaneous breakages without deletion of ABL1.