High fms-like tyrosine kinase-3 (FLT3) receptor surface expression predicts poor outcome in FLT3 internal tandem duplication (ITD) negative patients in adult acute myeloid leukaemia: A prospective pilot study from India

Mitochondrial complex II and V activity is enhanced in pediatric acute myeloid leukemia

BACKGROUND

Mitochondrial bioenergetic alterations are commonly observed metabolic adaptation in malignancies including acute myeloid leukemia (AML). Mitochondrial DNA alterations are well known in pediatric AML with possible prognostic significance; however, mitochondrial complex activity and its impact on disease outcome have not been previously explored. The aim of this study was to evaluate the mitochondrial complex II and complex V activity and its prognostic significance in pediatric AML patients.

METHODS

Consecutive 82 de novo pediatric (≤18 years) patients with AML were included in the study along with age and sex matched controls. Bone marrow mononuclear cells were isolated from baseline bone marrow samples from all patients and controls. DNA, RNA and proteins were extracted and relative expression of mitochondrial biogenesis genes TFAM, POLG, POLRMT were estimated along with mitochondrial DNA copy number. The mitochondrial complex II and V enzymes were immunocaptured and their activity was measured by substrate specific absorbance change by kinetic ELISA. The mitochondrial complex II and V activity was compared with controls and their association with clinico-pathological features and survival outcome were analysed. Complex activity was also correlated with relative expression of biogenesis genes.

RESULTS

The activity of mitochondrial complex II and V were found to be significantly enhanced (P = 0.010 and P = 0.0013 respectively) in pediatric AML patients compared to controls. The activity of mitochondrial complex II and V showed significant positive correlation with relative gene expression of mitochondrial biogenesis genes TFAM (P = 0.001 and P = 0.016 respectively) and POLG (P = 0.005 and P = 0.006 respectively). Neither of the two complex activities showed any significant association with baseline disease demographics or any clinico-pathological feature. Furthermore, the complex II and V activity did not show any impact on event free survival (P = 0.25 and P = 0.24 respectively) and overall survival (P = 0.14 and P = 0.17 respectively) in our cohort.

CONCLUSION

The activity of both mitochondrial complex II and V are significantly elevated in bone marrow mononuclear cells of children with AML compared to controls. The enhanced activity may be related to upregulation of mitochondrial biogenesis genes TFAM and POLG. The enhanced activity of either of the complexes did not impact disease biology or survival outcomes in pediatric AML.

Prognostic Significance of Fms-Like Tyrosine Kinase 3 Internal Tandem Duplication Mutation in Non-Transplant Adult Patients with Acute Myeloblastic Leukemia: A Systematic Review and Meta-Analysis

Background:

Fms-like tyrosine kinase-3, internal tandem duplication (FLT3-ITD) mutation, is a known predictor for worse outcome in patients with acute myeloblastic leukemia (AML). However, the prognostic significance of FLT3-ITD mutation in adult, non-transplant patients is still unclear therefore we conducted a systematic review and meta-analysis to explain this issue. The main outcome was overall survival (OS), while additional outcomes included event-free survival (EFS).

Methods:

Seven Databases (ScienceDirect, Scopus, PubMed, Cochrane, SpringerLink, ProQuest, and EBSCOhost) were searched up to August 2020. Studies investigating the prognostic value of AML in adults with FLT3-ITD mutational status were selected. Studies which patients had received transplantation, diagnosed with acute promyelocytic leukemia (APL) or secondary AML were excluded. The selected studies were divided into subgroups based on their cytogenetic profile. Summary hazard ratios (HR) and 95% confidence intervals (CI) were calculated using fixed-effects models. Heterogeneity tests were conducted and presented in I₂ value. Forest plot was presented to facilitate understanding of the results. Publication bias was analyzed by Funnel Plot test.

Results:

A total of ten studies describing research conducted from 1999 to 2020, met the inclusion criteria for this study. Nine studies reported OS and four studies reported EFS in HR. The highest HR for OS is 6.33 (95% CI, 2.61-15.33; p < 0.001), for EFS is 3.58 (95% CI, 1.59 – 8.05); p = 0.002)., while the lowest for OS is 1.33 (95% CI, 0.88-2.01; P = 0.174) and for EFS is 1.29 (95% CI, 0.75-2.23; p = 0.34). Nine studies were included in meta-analysis with HR for OS 1.91 (95% CI, 1.59–2.30, p < 0.00001), whereas 4 studies were included in meta-analysis for EFS with HR 1.64 (95% CI, 1.25–2.14; p = 0.0003).

Conclusion:

FLT3-ITD mutation is associated with worse prognosis in adult, non-transplant patients with AML, both for OS and EFS.

Prognostic impact of mitochondrial DNA D-loop variations in pediatric acute myeloid leukemia

The role of mitochondrial DNA (mt-DNA) changes, especially those in the regulatory D-loop region in Acute Myeloid Leukemia (AML) remains investigational. Consecutive 151 de novo pediatric AML patients, (≤18 yr) were prospectively enrolled from June 2013-August 2016, to assess the prognostic impact of mt-DNA D-loop variations (somatic/germline) on survival. For each patient, D-loop region was sequenced on baseline bone marrow and buccal swab, and mother’s blood sample. In 151 AML subjects, 1490 variations were found at 237 positions; 80.9% were germline and 19.1% somatic. The mean number of variations per position was 6.3. Variations with frequency ≥6 were analyzed for their impact on survival and 4 categories were created, namely “somatic-protective”, “somatic-hazardous”, “germline-protective” and “germline- hazardous”. Although, somatic-protective could not predict event free survival (EFS) or overall survival (OS), somatic-hazardous [(OS) HR = 2.33, p = 0.06] and germline-hazardous [(OS) HR = 2.85, p < 0.01] significantly predicted OS and EFS. Notably, the germline-protective, could significantly predict EFS (HR = 0.31, p = 0.03) and OS (HR = 0.19, p < 0.01), only when variations at ≥2 positions were present. On multivariate analysis, three positions namely 16111, 16126, 16362 and karyotype were found to be predictive of EFS. A prognostic index (PI) was developed using nomogram PI = (0.8*karyotype) + (1.0*c16111) + (0.7*t16362) + (1.2*t16126). Hazard ratio for EFS increased significantly with increasing PI reaching to a maximum of 3.3 (p < 0.01). In conclusion, the impact of mt-DNA D-loop variations on outcomes in pediatric AML depends on their nature (germline/somatic), position and mutational burden, highlighting their potential role as evolving prognostic biomarkers.