Molecular studies reveal MLL-MLLT10/AF10 and ARID5B-MLL gene fusions displaced in a case of infantile acute lymphoblastic leukemia with complex karyotype

Assessment of differentially methylated loci in individuals with end-stage kidney disease attributed to diabetic kidney disease: an exploratory study

BACKGROUND

A subset of individuals with type 1 diabetes mellitus (T1DM) are predisposed to developing diabetic kidney disease (DKD), the most common cause globally of end-stage kidney disease (ESKD). Emerging evidence suggests epigenetic changes in DNA methylation may have a causal role in both T1DM and DKD. The aim of this exploratory investigation was to assess differences in blood-derived DNA methylation patterns between individuals with T1DM-ESKD and individuals with long-duration T1DM but no evidence of kidney disease upon repeated testing to identify potential blood-based biomarkers. Blood-derived DNA from individuals (107 cases, 253 controls and 14 experimental controls) were bisulphite treated before DNA methylation patterns from both groups were generated and analysed using Illumina's Infinium MethylationEPIC BeadChip arrays (n = 862,927 sites). Differentially methylated CpG sites (dmCpGs) were identified (false discovery rate adjusted p ≤ × 10^-8 and fold change ± 2) by comparing methylation levels between ESKD cases and T1DM controls at single site resolution. Gene annotation and functionality was investigated to enrich and rank methylated regions associated with ESKD in T1DM.

RESULTS

Top-ranked genes within which several dmCpGs were located and supported by functional data with methylation look-ups in other cohorts include: AFF3, ARID5B, CUX1, ELMO1, FKBP5, HDAC4, ITGAL, LY9, PIM1, RUNX3, SEPTIN9 and UPF3A. Top-ranked enrichment pathways included pathways in cancer, TGF-β signalling and Th17 cell differentiation.

CONCLUSIONS

Epigenetic alterations provide a dynamic link between an individual's genetic background and their environmental exposures. This robust evaluation of DNA methylation in carefully phenotyped individuals has identified biomarkers associated with ESKD, revealing several genes and implicated key pathways associated with ESKD in individuals with T1DM.

MLLT10 in benign and malignant hematopoiesis

Non-random chromosomal translocations involving the putative transcription factor Mixed Lineage Leukemia Translocated to 10 (MLLT10, also known as AF10) are commonly observed in both acute myeloid and lymphoid leukemias and are indicative of a poor prognosis. Despite the well-described actions of oncogenic MLLT10 fusion proteins, the role of wild-type MLLT10 in hematopoiesis is not well characterized. The protein structure and several interacting partners have been described and provide indications as to the potential functions of MLLT10. This review examines these aspects of MLLT10, contextualizing its function in benign and malignant hematopoiesis.

The Role of ARID5B in Acute Lymphoblastic Leukemia and Beyond

Acute lymphoblastic leukemia (ALL) is the most common malignancy in children with distinct characteristics among different subtypes. Although the etiology of ALL has not been fully unveiled, initiation of ALL has been demonstrated to partly depend on genetic factors. As indicated by several genome wide association studies (GWASs) and candidate gene analyses, ARID5B, a member of AT-rich interactive domain (ARID) protein family, is associated with the occurrence and prognosis of ALL. However, the mechanisms by which ARID5B genotype impact on the susceptibility and treatment outcome remain vague. In this review, we outline developments in the understanding of ARID5B in the susceptibility of ALL and its therapeutic perspectives, and summarize the underlying mechanisms based on the limited functional studies, hoping to illustrate the possible mechanisms of ARID5B impact and highlight the potential treatment regimens.

Relatively favorable prognosis for MLL-rearranged childhood acute leukemia with reciprocal translocations

BACKGROUND

Mixed-lineage leukemia (MLL) with multifarious partner genes leads to aggressive leukemia with dismal outcomes.

METHODS

Using panel-based targeted sequencing, we examined 90 cases with MLL-rearranged (MLL-r) childhood acute leukemia, including 55 with acute lymphoblastic leukemia (ALL) and 35 with acute myeloid leukemia (AML).

RESULTS

MLL breakpoints and complete rearrangements were identified. A total of 37.8% (34/90) of patients displayed a single direct MLL fusion gene, 15.6% (14/90) carried a single reciprocal fusion, and 27.8% (25/90) had both reciprocal MLL fusion alleles. The remaining 17 MLL-r cases exhibited complex translocations with homozygous disruptions on chromosome 11 or two breakpoints on the same MLL allele with a deletion of functional regions. A total of 77 patients (45 ALL and 32 AML) received chemotherapy with a median follow-up of 2.5 years. Unexpectedly, we identified children with reciprocal MLL fusions who exhibited relatively favorable outcomes compared with those in children with complex translocations or a single direct MLL fusion allele (66.1% vs. 24.6% and 27.6%, P = 0.001). Reciprocal MLL fusion may be functionally rescued by a partially truncated MLL protein.

CONCLUSION

Comprehensive MLL-r analysis by targeted next-generation sequencing can provide detailed molecular information and is helpful for precise stratified treatment and clinical prognosis determination.