Cytogenetics affect diagnosis and prognosis in pediatric acute myeloid leukemia (AML), a rare type of cancer in children. Although outcomes have improved and survival rates are around 70%, about 30% of patients relapse.
A review article published in Genes provided updated details on cytogenetics in pediatric AML, with a focus on de novo AML, which represents about 95% of cases. Pediatric patients respond better to intensive therapy, and defining cytogenetics at diagnosis helps patients benefit from tailored therapy.
About 75% to 80% of children with pediatric AML have clonal, acquired, somatic cytogenetic abnormalities (CAs) detected.
The World Health Organization (WHO) has an AML classification that includes cytogenetic and morphological characteristics. Patients may be categorized as good, intermediate, or adverse prognosis.
Pediatric AML differs from adult AML in that the most frequent CAs are balanced chromosomal rearrangements. Acute promyelocytic leukemia (APL) accounts for about 5 to 10% of pediatric AML cases. Certain genetic mutations affect the prognosis of APL, although effective targeted treatments are available for some cases.
Core binding factor (CBF) AML accounts for about 25% of pediatric AML cases. The authors note that CBF leukemias have a good prognosis of more than 80%, but they still have a relapse rate of around 30%.
Other more rare balanced rearrangements have been associated with an intermediate or adverse prognosis. Some of these rarer rearrangements do not have a prognosis established yet.
Patients may also have unbalanced CAs. Monosomy 7 and deletion of the long arm of chromosome 7, del(7q), may present as secondary abnormalities in pediatric AML. Monosomy 7 is associated with a poor prognosis whereas del(7q) is associated with an intermediate prognosis.
About 10% to 14% of pediatric AML cases also have trisomy 8, often associated with another cytogenetic change.
Cytogenetics and molecular subtypes of pediatric AML also vary by age. Infants tend to have fewer favorable cytogenetics compared to children 2 years and older. Myelodysplastic syndromes (MDS) are less common in pediatric patients, but GATA2 germline mutation may predispose patients to AML and MDS.
Evaluating pediatric patients based on cytogenetics and molecular subtypes helps match patients to risk-adapted therapies.
Quessada J, Cuccuini W, Saultier P, et al. Cytogenetics of pediatric acute myeloid leukemia: a review of the current knowledge. Genes (Basel). 2021;12(6):924. doi:10.3390/genes12060924