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.