Chromosomal abnormalities in patients with haematologic malignancies in the General Hospital of Mexico

Background: Haematologic malignancies are generated by alterations in haematopoietic stem cells. Chromosomal rearrangements are present in >50% of patients and are useful as diagnostic and prognostic factors.Objective: In this study we describe the cytogenetic characteristics observed in patients with haematological malignancies in the Genetics Department during the period 2000–2014.Material and Methods: The karyotype was performed on bone marrow (85%) and peripheral blood (15%) with conventional techniques in 9717 samples.Results: The average age was 40 years (range 0.3–95) and the male/female distribution was 50.5%/49.5%. 352 cases (3.6%) were paediatric with a male/female distribution of 59/41%. The diagnosis was: acute leukaemia 4445 (45.7%), CML 2058 (20.4%), and MDS or some form of cytopenia 1573 (16%). Fewer than 5% of samples received were from AA, MM, CMPD, NHL, CLL, LPD and others. The distribution of acute leukaemia was: ALL 44%, AML 43% and unspecified 13%; the predominant subtypes were ALL-L2 at 50.7% and AML-M3 at 54.2%. Only 61% of the 9717 samples were processed. The karyotype was normal in 3956 (66.7%) samples, the rest (1972, 33.3%) had chromosomal abnormalities: 65% structural and 35% numerical. The changes observed most frequently were t(9;22)(q34;q11) 26%, hyperdiploidy/polyploidy 19.3%, diverse translocations 8.4%, hypodiploidy 8%, t(15;17)(q22;q12) 7.8%, and MDS-related disorders (del5q/-5/-7/+8) 7.7%. Different deletions, trisomy, monosomy and/or complex karyotype were present in smaller proportion (<7%).Conclusions: The karyotype remains useful to confirm the diagnoses, establish risk-based prognoses, and classify based on risk to patients; for example in cases with t(9;22) in CML or t(15;17) in M3