Dilhan Kuru

CYTOGENETIC CLONAL EVOLUTION IN PATIENTS WITH CHRONIC MYELOID LEUKEMIA

ABSTRACT Chronic myeloid leukaemia (CML) is a clonal haematological disease characterised by t(9;22)(q34;q11) which is called Philadelphia (Ph) chromosome. Highly improved haematological and cytogenetic results were obtained in chronic phase CML with the introduction of imatinib. Occurrence of additional cytogenetic abnormalities in Ph(+) cells is defined as clonal evolution (CE) and considered to be a preceding sign for acceleration. The most common additional chromosomal changes are +8, +Ph, i(17q), +19, -Y, +21, +17 and-7. The aims of this study were to delineate the occurrence pattern of cytogenetic clonal evolution in our cohort of CML patients and to investigate the impact on the course and prognosis of CML. Additional clonal chromosomal changes in Ph(+) cells were observed in 20 cases (19%). The abnormalities seen were monosomy 21 (%35), -17 (%30), -19 and +8 in (%25), -7, -8, -13, -15, -22, +Ph, and different marker chromosomes (%20), -Y, -12, -14, -16, -20 (%15), +Y, -10, -18 (%10), and -X, -3, -9, +20, der(7;17)(q10;q10), der3?, der12? (%5). The findings of-Y, -7, -8, +8, -14, -15, -17, -18, -21, +Ph, der(7;17)(q10;q10) and del(7)(q11) have been recorded in more than one samples in at least one case. The clinical data of the 20 cases with CE were compared to 7 cases with no or minor cytogenetic response without CE and no statistically significant differences found. Considering their high frequency and persistence in successive samples, we recommend to trace -21 and -17 with FISH in addition to classical cytogenetics in CML cases.

Variant Philadelphia translocations with different breakpoints in six chronic myeloid leukemia patients.

OBJECTIVE The Philadelphia (Ph) chromosome, consisting of the t(9;22)(q34;q11) translocation, is observed in ~90% of patients with chronic myeloid leukemia (CML). Variant Ph translocations are observed in 5%-10% of CML patients. In variant translocations 3 and possibly more chromosomes are involved. Herein we report 6 CML patients with variant Ph translocations. METHODS Bone marrow samples were examined using conventional cytogenetic meth ods. Fluorescence in situ hybridization (FISH) with whole-chromosome paints and BCR-ABL 1D probes were used to confirm and/or complement the findings, and identify rearrangements beyond the resolution of conventional cytogenetic methods. RESULTS Variant Ph translocations in the 6 patients were as follows: t(7;22)(p22;q11), t(9;22;15)(q34;q11;q22), t(15;22)(p11;q11), t(1;9;22;3)(q24;q34;q11;q21), t(12;22)(p13;q11), and t(4;8;9;22)(q11;q13;q34;q11). CONCLUSION Among the patients, 3 had simple and 3 had complex variant Ph translocations. Two of the presented cases had variant Ph chromosomes not previously described, 1 of which had a new complex Ph translocation involving chromosomes 1, 3, 9, 22, and t(1;9;22;3)(q24;q34;q11;q21) apart from a clone with a classical Ph, and the other case had variant Ph translocation with chromosomes 4, 8, 9, and 22, and t(4;8;9;22)(q11;q13;q34;q11) full complex translocation. Number of studies reported that some patients with variant Ph translocation were poor responders to imatinib. All of our patients with variant Ph translocations had suboptimal responses to imatinib, denoting a poor prognosis also. Variant Ph translocations may be important as they are associated with prognosis and therapy for CML patients.

Recurrent Monosomies Confirmed by Interphase FISH in Three Chronic Myeloid Leukemia Cases

Although chronic myeloid leukemia (CML) is characterized by the Philadelphia (Ph) chromosome, which is the result of t(9;22) (q34;q11) or its variants, 10%-20% of cases have additional cytogenetic abnormalities. The most common additional abnormalities are loss of the Y chromosome, +8, +Ph, and i(17q). Since these additional chromosome abnormalities are signs of disease progression, it is important to perform cytogenetic analyses periodically in patients with CML [1].