Cytogenetics of acute myeloid leukemia – chromosomal aberrations

It is assumed that non-random acquired chromosomal aberrations exist in all patients with acute non-lymphoblastic leukemia (ONLL), but are determined using various methods in 70-80%. Detection of karyotype abnormalities allows us to predict the course of the disease and track the minimal residual population of leukemic cells.

Certain associations between cytogenetic and clinico-morphological features have been discussed previously. Fundamentally, at present, cytogenetic markers are becoming decisive in the choice of therapeutic approaches that were previously absolutely standard for all AML variants.

The most frequently detected cytogenetic abnormalities in acute myeloid leukemia include trisomy of chromosome 8, t (15; 17), t (8; 21), inv16, del 5q, 7q, monosomy of chromosome 5 and 7, translocation involving the region 11q23. As previously noted, leukemias with t (15; 17), t (8; 21), invl6 and 11q23 anomaly are classified in a modern category in a separate category. It should be emphasized that if the number of blast cells is less than 20%, but t (15; 17), inv16, t (8; 21) are detected, then the diagnosis of AML is nonetheless established.

Many cytogenetic aberrations, as a result of which one or another chimeric gene appears, can serve as a marker of a tumor clone in the period of clinical and hematological remission, i.e., used to monitor minimal residual disease. The table presents the most widely used in clinical practice molecular markers and the frequency of their occurrence in ONLL.

Unfortunately, when performing reverse transcriptase and direct polymerase chain reactions to determine the minimum residual population of leukemic cells, there are both false positive and false negative results.

The most common cause of false-positive results is not sufficiently accurate execution of the reaction, not in perfectly clean conditions, but false negative – in cases where transcription of mRNA is not detected in clonogenic leukemic cells with a certain chromosomal translocation.

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