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Clonal dominance is an adverse prognostic factor in acute myeloid leukemia treated with intensive chemotherapy.

Marco CerranoMatthieu DuchmannRathana KimLoic VasseurPierre HirschXavier ThomasSamuel QuentinJustine PasanisiMarie PassetFlorence RabianRamy RahméEtienne LenglinéEmmanuel RaffouxNathalie DhédinMarie SébertOdile MaarekAnna RaimbaultKarine Celli-LebrasLionel AdèsPierre FenauxNicolas BoisselFrançois DelhommeauJean SoulierHervé DombretEmmanuelle ClappierPierre SujobertRaphaël A Itzykson
Published in: Leukemia (2020)
Intra-tumor heterogeneity portends poor outcome in many cancers. In AML, a higher number of drivers worsens prognosis. The Shannon Index is a robust metric of clonal heterogeneity that accounts for the number of clones, but also their relative abundance. We show that a Shannon Index can be estimated from bulk sequencing, which is correlated (ρ = 0.76) with clonal diversity from single-colony genotyping. In a discovery cohort of 292 patients with sequencing of 43 genes, a higher number of drivers (HR = 1.18, P = 0.028) and a lower Shannon Index (HR = 0.68, P = 0.048), the latter reflecting clonal dominance, are independently associated with worse OS independently of European LeukemiaNet 2017 risk. These findings are validated in an independent cohort of 1184 patients with 111-gene sequencing (number of drivers HR = 1.16, P = 1 × 10-5, Shannon Index HR = 0.81, P = 0.007). By re-interrogating paired diagnosis/relapse exomes from 50 cytogenetically normal AMLs, we find clonal dominance at diagnosis to be correlated with the gain of a significantly higher number of mutations at relapse (P = 6 × 10-6), hence with clonal sweeping. Our results suggest that clonal dominance at diagnosis is associated with the presence of a leukemic phenotype allowing rapid expansion of new clones and driving relapse after chemotherapy.
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