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Acute myeloid leukemia (AML) is a highly heterogeneous disease both in terms of genetic background and response to chemotherapy. Although molecular aberrations are routinely used to stratify AML patients into prognostic subgroups when receiving standard chemotherapy, the predictive value of the genetic background and co-occurring mutations remains to be assessed when using newly approved antileukemic drugs. In the present study, we retrospectively addressed the question of the predictive value of molecular events on the benefit of the addition of gemtuzumab ozogamicin (GO) to standard front-line chemotherapy. Using the more recent European LeukemiaNet (ELN) 2017 risk classification, we confirmed that the benefit of GO was restricted to the favorable (hazard ratio [HR], 0.54, 95% confidence interval [CI], 0.30-0.98) and intermediate (HR, 0.57; 95% CI, 0.33-1.00) risk categories, whereas it did not influence the outcome of patients within the adverse risk subgroup (HR, 0.93; 95% CI, 0.61-1.43). Interestingly, the benefit of GO was significant for patients with activating signaling mutations (HR, 0.43; 95% CI, 0.28-0.65), which correlated with higher CD33 expression levels. These results suggest that molecular aberrations could be critical for future differentially tailored treatments based on integrated genetic profiles that are able to predict the benefit of GO on outcome.

A multistage model instructed by a large dataset (knowledge bank [KB] algorithm) has recently been developed to improve outcome prediction and tailor therapeutic decision, including hematopoietic stem cell transplantation (HSCT) in AML. We assessed the performance of the KB in guiding HSCT decision in first complete remission (CR1) in 656 AML patients younger than 60 years from the ALFA-0702 trial (NCT00932412). KB predictions of Overall Survival (OS) were superior to those of European LeukemiaNet (ELN) 2017 risk stratification (C-index 68.9 versus 63.0). Among patients reaching CR1, HSCT in CR1, as a time-dependent covariate was detrimental in those with favorable ELN 2017 risk and those with negative NPM1 MRD (interaction tests P=0.01 and P=0.02, respectively). Using KB simulations of survival at 5 years in a scenario without HSCT in CR1 (KB score), we identified in a similar time-dependent analysis a significant interaction between the KB score and HSCT, with HSCT in CR1 being detrimental only in patients with a good prognosis based on KB simulations (KB score ≥40, interaction test P=0.01). We could finally integrate ELN 2017, NPM1 MRD and KB scores to sort 545 CR1 patients into 278 (51.0%) HSCT candidates and 267 (49.0%) chemo-only candidates. In both time-dependent and 6-month landmark analyses, HSCT significantly improved OS in HSCT candidates while it significantly shortened OS in chemo-only candidates. Integrating KB predictions with ELN 2017 and MRD may thus represent a promising approach to optimize HSCT timing in younger AML patients.

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We report a case of myeloproliferative neoplasm (MPN) with an atypical t(9;22;15)(p24;q11;q21) translocation, leading to a BCR-JAK2 fusion, associated with a trisomy of chromosome 8 in clonal evolution at karyotype. Patient's evolution was marked by an aggressive clinical course with rapid progression to blast phase within the first year after diagnosis. Examination of matched chronic phase and blast crisis samples by SNP-array karyotyping identified secondary acquired cryptic genetic events at the time of lymphoblastic transformation, including biallelic IKZF1 alteration and EBF1 and CDKN2A/B codeletions. This case is the first report describing acquisition of secondary genetic events leading to acute lymphoblastic progression in a rare MPN with BCR-JAK2 fusion.

BackgroundOur aim was to set the FISH combination of del(17p13), t(4;14), 1q21 gain and del(1p32), four adverse cytogenetic factors rarely evaluated together, and compare our technical thresholds with those defined in the literature.MethodsTwo hundred thirty-three patients with MM at diagnosis were studied using FISH to target 4 unfavorable cytogenetic abnormalities: 17p13 deletion, t(4;14) translocation, 1p32 deletion and 1q21 gain. Technical thresholds were determined for each probe using isolated CD138-expressing PC from patients without MM.ResultsThe FISH analysis identified abnormalities in 79.0% of patients. Del(17p13) was detected in 15.0% of cases, t(4;14) in 11.5%, 1q21 gain in 37.8% and del(1p32) in 8.7%. Adding 1p32/1q21 FISH probes has enabled us to identify adverse cytogenetic profiles in 39.0% of patients without del(17p13) or t(4;14). Clonal heterogeneity was observed in 51.1% of patients as well as an increase in the number of adverse abnormalities when related clones were greater than or equal to 2 (85.1% against 45.6%).ConclusionFISH allowed detecting accumulation of adverse abnormalities and clonal heterogeneity in MM with a combination of 4 probes. The impacts of these two parameters need to be evaluated, and could be included in future cytogenetic classifications.

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Key Clinical MessageThe prognosis of patients with marrow necrosis secondary to neoplastic disease (often gastric adenocarcinoma) was found to be extremely poor with a median overall survival (OS) of few months. This case confirms the very poor prognosis and shows an association with a neural endocrine adenocarcinoma of the thymus.