NGS in AML Relapse

Acute myeloid leukemia (AML) relapse is often associated with a clonal evolution at the cytogenetic and molecular level and therefore represents a challenge in the treatment of AML. Targeted sequencing is now usually done at diagnosis in AML, as only a small core group of genes is frequently mutated in AML and myelodysplastic syndromes. This approach, contrary to WGS is cheaper, together with a rapid turnaround and high sequencing coverage depths allowing the detection of variant allele fractions as low as 2%. In the investigator's center, targeted analysis of AML patients is routinely realized at diagnosis and at relapse. In thses patients, five different clonal evolution patterns including cytogenetic and molecular analysis at relapse will be evaluated: (1) Stability, defined by no clonal change, (2) Gain, strictly defined by acquisition of additional variations (mutations or cytogenetic alterations), (3) Loss, strictly defined by loss of variants or regression, (4) Gain and Loss, indicating the combination of both Gain and Loss patterns, (5) Emergence, defined by the emergence of alterations that were unrelated to those found at diagnosis. Karyotype and the mutations of up to 40 AML patients benefited from targeted NGS in the clinical hematology laboratory of the Hopitaux Universitaires de Strasbourg both at the time of the diagnosis of and the relapse will be studied, together with clinical and other biological characteristics.