Beschreibung:
AbstractBackgroundThe cytogenetic aberrations inv(16)(p13.1q22)/t(16;16)(p13.1;q22), frequently detected in acute myelomonocytic leukemia with eosinophilia (FAB type M4eo), are generally considered a prognostically favorable subgroup. M4eo comprises a distinct morphology compared to M4 without eosinophilia (M4eo‐) and therefore may be indicative for a different pathogenesis.ProceduresMorphology and cytogenetic/molecular analyses of a Dutch cohort of pediatric acute myelomonocytic leukemia (AML‐M4) patients were performed and studied in order to analyze the association between the presence of eosinophilia morphology (M4eo+), inv(16)/t(16;16) (inv(16)+), clinical features, and outcome.ResultsOf the 119 included patients with available combined morphological and cytogenetic results, 60% had M4eo‐ without inv(16) (inv(16)‐), 10% had M4eo‐/inv(16)+, 13% had M4eo+/inv(16)‐, and 17% had M4eo+/inv(16)+. M4eo+ was significantly associated with the presence of inv(16)/t(16;16) (P < 0.001). Patients with M4eo+ had no significantly superior outcome compared with patients with M4eo‐, whereas patients with inv(16)+ had significantly superior probabilities of event‐free survival and probabilities of overall survival compared with patients without inv(16)‐. Patients with M4eo+/inv(16)+ had no significantly better outcome than those with M4eo‐/inv(16)+.ConclusionThe prognostically favorable impact of distinct morphology with eosinophilia probably relies on its association with inv(16)/t(16;16). Simultaneous presence of both eosinophilia and inv(16) was not associated with superior outcome in our study. These results may be relevant for risk‐group classification and risk‐group adapted treatment and underline the importance of accurate cytogenetic analysis.