AML with inv(16)/t(16;16) and high-risk cytogenetic abnormalities: atypical features and unfavorable outcome

OBJECTIVES

Acute myeloid leukemia (AML) with inv(16)/t(16;16) is among the most frequent AML subtypes. It is recognized by the detection of the CBFB-MYH11 fusion which confers a favorable prognosis, irrespective of the presence of secondary cytogenetic abnormalities. However, the effect of additional genetic anomalies on the behavior of inv(16) AML is debatable. Recent case reports describe an unfavorable prognosis for those patients, characterized by early relapse and death. In this study, we present a series of patients with CBFB-MYH11 fusion and high-risk rearrangements to increase knowledge about this potentially distinct subgroup.

METHODS

All cases with inv(16)/ t(16;16) and one or more high risk abnormalities were reviewed at two tertiary healthcare centers between years 2006 and 2020 in terms of demographics, biological and clinical data.

RESULTS

Among the total 1447 and 1283 AML cases, the frequency was found to be 0,2% and 0.3%. Clinical data could be retrieved for 5 patients. Detected high-risk abnormalities included TP53 and 5q deletion, complex and monosomal karyotype. The median age was 67 years, with a majority of females (M:F = 1:1.5). Two out of 5 patients presented with therapy related AML, with short latency periods. All patients presented with thrombocytopenia and/or leukocytopenia. Bone marrow aspirates revealed atypical morphology and the detection of rare CBFB-MYH11 fusion transcripts. All 5 patients died, with a short mean overall survival of 5.8 months.

DISCUSSION AND CONCLUSION

Our series suggests that the presence of high risk abnormalities confers distinct biological features and poor prognosis to inv(16) AML.

Paediatric chronic myeloid leukaemia presenting in de novo or secondary blast phase - a comparison of clinical and genetic characteristics

Additional data on blast phase (BP) chronic myeloid leukaemia (CML) in children and adolescents is essential for improving diagnostic and therapeutic approaches of this rare but serious condition. Here, we describe distinct clinical and genetic characteristics of 18 paediatric patients with de novo (n = 10) and secondary (n = 8) BP CML enrolled in the CML-PAED-II trial and registry. Our findings suggest that paediatric patients exhibit a diverse cytogenetic profile compared to adults with BP CML. In addition, patients with de novo BP CML in this cohort presented at a younger age, whereas patients with secondary BP CML more often harboured complex karyotypes.

Associations between pretherapeutic body mass index, outcome, and cytogenetic abnormalities in pediatric acute myeloid leukemia

Background

Associations between body mass index (BMI), outcome, and leukemia‐related factors in children with acute myeloid leukemia (AML) remain unclear. We investigated associations between pretherapeutic BMI, cytogenetic abnormalities, and outcome in a large multinational cohort of children with AML.

Methods

We included patients, age 2‐17 years, diagnosed with de novo AML from the five Nordic countries (2004‐2016), Hong Kong (2007‐2016), the Netherlands and Belgium (2010‐2016), and Canada and USA (1995‐2012). BMI standard deviations score for age and sex was calculated and categorized according to the World Health Organization. Cumulative incidence functions, Kaplan‐Meier estimator, Cox regression, and logistic regression were used to investigate associations.

Results

In total, 867 patients were included. The median age was 10 years (range 2‐17 years). At diagnosis, 32 (4%) were underweight, 632 (73%) were healthy weight, 127 (15%) were overweight, and 76 (9%) were obese. There was no difference in relapse risk, treatment‐related mortality or overall mortality across BMI groups. The frequency of t(8;21) and inv(16) increased with increasing BMI. For obese patients, the sex, age, and country adjusted odds ratio of having t(8;21) or inv(16) were 1.9 (95% confidence interval (CI) 1.1‐3.4) and 2.8 (95% CI 1.3‐5.8), respectively, compared to healthy weight patients.

Conclusions

This study did not confirm previous reports of associations between overweight and increased treatment‐related or overall mortality in children. Obesity was associated with a higher frequency of t(8;21) and inv(16). AML cytogenetics appear to differ by BMI status.

Incidence and prognostic impact of cytogenetic aberrations in patients with systemic mastocytosis

The clinical behavior of systemic mastocytosis (SM) is strongly associated with activating mutations in KIT (D816V in >80% of cases), with the severity of the phenotype influenced by additional somatic mutations, for example, in SRSF2, ASXL1, or RUNX1. Complex molecular profiles are frequently associated with the presence of an associated hematologic neoplasm (AHN) and an unfavorable clinical outcome. However, little is known about the incidence and prognostic impact of cytogenetic aberrations. We analyzed cytogenetic and molecular characteristics of 109 patients (KIT D816V+, n = 102, 94%) with indolent (ISM, n = 26) and advanced SM (n = 83) with (n = 73, 88%) or without AHN. An aberrant karyotype was identified in SM-AHN (16/73, 22%) patients only. In patients with an aberrant karyotype, additional somatic mutations were identified in 12/16 (75%) patients. Seven of 10 (70%) patients with a poor-risk karyotype, for example, monosomy 7 or complex karyotype, and 1/6 (17%) patients with a good-risk karyotype progressed to secondary acute myeloid leukemia (n = 7) or mast cell leukemia (n = 1) within a median of 40 months (range 2-190, P = .04). In advanced SM, the median overall survival (OS) of poor-risk karyotype patients was significantly shorter than in good-risk/normal karyotype patients (4 vs 39 months; hazard ratio 11.7, 95% CI 5.0-27.3; P < .0001). Additionally, the shortened OS in patients with poor-risk karyotype was independent from the mutation status. In summary, a poor-risk karyotype is an independent prognostic variable in advanced SM. Cytogenetic and molecular analyses should be routinely performed in all patients with advanced SM ± AHN because these investigations greatly support prognostication and treatment decisions.

Clinical impact of KMT2C and SPRY4 expression levels in intensively treated younger adult acute myeloid leukemia patients

OBJECTIVE

To evaluate the prognostic impact of gene expression levels (ELs) of two tumor suppressor genes, sprouty 4 (SPRY4, located on 5q) and lysine methyltransferase 2C (KMT2C, located on 7q) in correlation with clinical characteristics and genetic abnormalities assessed at initial diagnosis in acute myeloid leukemia (AML).

METHOD

Gene expression levels were measured on cDNA by RT-qPCR from diagnostic bone marrow samples of 275 intensively treated adult AML patients (median age, 48 years).

RESULTS

KMT2C ELs were significantly lower in abn7q/-7 (P = .001), whereas SPRY4 ELs were not associated with abn5q/-5. Higher KMT2C and SPRY4 ELs were significantly associated with lower genetic risk groups as defined by the European LeukemiaNet classification. Additionally, KMT2C ELs were lower in cytogenetically normal patients with DNMT3A (P = .01) or FLT3-ITD mutations (P = .05). KMT2C ELs were not associated with prognosis, whereas higher SPRY4 ELs showed a favorable impact on event-free (EFS, P = .01), relapse-free (RFS, P = .01) and in-trend on overall survival (P = .06) for cytogenetically abnormal patients, which was confirmed in multivariable analysis for EFS (HR, 0.84; 95%-CI, 0.73-0.97; P = .02) and RFS (HR, 0.85; 95%-CI, 0.73-0.98; P = .02).

CONCLUSION

Our data indicate that KMT2C ELs are associated with specific genetic features and that SPRY4 ELs may add prognostic information.

Clinical Prognostic Factors in 86 Chinese Patients with Primary Myelodysplastic Syndromes and Trisomy 8: A Single Institution Experience

PURPOSE

The objective was to determine the characteristics and prognostic factors of 86 Chinese patients with trisomy 8 aberrations and compare the prognostic value of International Prognostic System (IPSS) and Revised IPSS (IPSS-R) in this cohort.

MATERIALS AND METHODS

A total of 86 cases diagnosed with primary myelodysplastic syndromes (MDS) with isolated tr8 or with tr8 and other additional cytogenetic aberrations diagnosed and treated at the Union Hospital, Tongji Medical College of Huazhong University of Science and Technology between July 2002 and March 2013 were reviewed.

RESULTS

The median survival of the entire group was 23.0 months, and acute myeloid leukemia (AML) developed in 43% (37/86) patients within the follow up time. The univariate analysis revealed that overall survival (OS) was correlated with age, thrombocytopenia, absolute neutrophil count, marrow blasts, cytogenetic status and red blood cell transfusion at diagnosis, and the multivariate analysis revealed that age, marrow blasts, cytogenetic status and transfusion dependence were independent parameters for the OS. The cytogenetic complexity and marrow blasts had the strongest impact on the AML transformation by multivariate analysis. Comparing the two prognostic systems, both two systems could successfully discriminate risk groups for survival. IPSS-R was more refined than IPSS for predicting OS, but had no advantage in predicting the risk of AML development.

CONCLUSION

This study confirmed the influence of clinical factors on the prognosis of 86 Chinese MDS patients with trisomy 8. In addition, IPSS-R can further refine prognostic discrimination in the IPSS risk categories.

Genetic aberrations in childhood acute lymphoblastic leukaemia: application of high-density single nucleotide polymorphism array

Screening of the entire human genome using high-density single nucleotide polymorphism array (SNPA) has become a powerful technique used in cancer genetics and population genetics studies. The GeneChip® Mapping Array, introduced by Affymetrix, is one SNPA platform utilised for genotyping studies. This GeneChip system allows researchers to gain a comprehensive view of cancer biology on a single platform for the quantification of chromosomal amplifications, deletions, and loss of heterozygosity or for allelic imbalance studies. Importantly, this array analysis has the potential to reveal novel genetic findings involved in the multistep development of cancer. Given the importance of genetic factors in leukaemogenesis and the usefulness of screening the whole genome, SNPA analysis has been utilised in many studies to characterise genetic aberrations in childhood acute lymphoblastic leukaemia.