Karyotypic characterisation in a series of 573 patients with chronic myeloid leukemia

Objective: At diagnosis, chronic myeloid leukemia (CML) is genetically characterized by the presence of the classical reciporocal translocation t(9 ; 22)(q34 ; q11.2), resulting in a BCR/ABL1 gene fusion on the derivate chromosome 22 called the Philadelphia (Ph) chromosome and occur usualy as the sole abnormality. In 5–10% of patients, a complex translocation leads to the formation of a variant Ph chromosome and involves not only chromosome 9 and 22, but also a third or more chromosomes. Cryptic BCR/ABL1 rearrangments can be found in cases with complex karyotype in wich the t(9 ; 22) is not detected by conventional cytogenetic analyses. Additional chromosomal abnormalities (ACAs) in Ph-positive cells may appear in 5% of cases and are strongly associated with disease progression. Methods: We cytogenetically investigated a group of 573 CML patients from 1988–2013 years. The CML group consisted of 306 males (median age 47) and 267 females (median age 51) (1, 2/1). Results: Complex variant translocation was demostrated in 49 patients (8%), six with criptic BCR/ABL1 fusion gene. Chromosome bands involved in structural rearrangments include 1q23, 2q37, 3q27, 3p21, 6p23, 6q23, 9p21, 9q34, 10q11, 10q12, 11p15, 11q13, 11q23, 12p13, 13p11, 14p11, 14q11, 15p11, 15q26, 16p13, 17q21, 18p12, 19p13, 21q22, 22q10 and Xp11. ACAs in Ph-positive are non-random (7, 5%), with the most common being +8, +Ph, i(17q), +19, +21, +17, -Y, and -7. Three patients were with clonal Robertson translocarion, one with t(8 ; 21). Konstitutional chromosome abnormalities were 45, X, 47, XXX, and translocation t(2 ; 8)(p11.2 ; p11). Conclusion: These results coincidence with those reported in literature.