Contribution of the TIME in BCP-ALL: the basis for novel approaches therapeutics

The bone marrow (BM) niche is a microenvironment where both immune and non-immune cells functionally interact with hematopoietic stem cells (HSC) and more differentiated progenitors, contributing to the regulation of hematopoiesis. It is regulated by various signaling molecules such as cytokines, chemokines, and adhesion molecules in its microenvironment. However, despite the strict regulation of BM signals to maintain their steady state, accumulating evidence in B-cell precursor acute lymphoblastic leukemia (BCP-ALL) indicates that leukemic cells can disrupt the physiological hematopoietic niche in the BM, creating a new leukemia-supportive microenvironment. This environment favors immunological evasion mechanisms and the interaction of these cells with the development and progression of BCP-ALL. With a growing understanding of the tumor immune microenvironment (TIME) in the development and progression of BCP-ALL, current strategies focused on "re-editing" TIME to promote antitumor immunity have been developed. In this review, we summarize how TIME cells are disrupted by the presence of leukemic cells, evading immunosurveillance mechanisms in the BCP-ALL model. We also explore the crosstalk between TIME and leukemic cells that leads to treatment resistance, along with the most promising immuno-therapy strategies. Understanding and further research into the role of the BM microenvironment in leukemia progression and relapse are crucial for developing more effective treatments and reducing patient mortality.

Analysis of non-alcoholic fatty liver disease during induction therapy for B-cell precursor acute lymphoblastic leukemia in children and adolescents

BACKGROUND

A prospective evaluation of non-alcoholic fatty liver disease (NAFLD) during induction therapy for acute lymphoblastic leukemia (ALL) has not been performed. Herein, we prospectively investigated the frequency, risk factors, and outcomes of NAFLD during induction therapy in children and adolescents with B-cell precursor ALL (BCP-ALL).

METHODS

This study enrolled 74 newly diagnosed BCP-ALL cases aged 1 year and older who were admitted to our department between January 2011 and December 2020. Median age was 6.6 years (1.3-17.5 years). Plain computed tomography (CT) of the upper abdomen was performed before induction therapy, and on days 15 and 29 after initiation of induction therapy. Patients with a liver/spleen CT ratio <0.9 were defined as having NAFLD.

RESULTS

The frequency of NAFLD was 73%. Patients with NAFLD had a higher rate of hypertriglyceridemia. There was no significant difference in 5-year overall survival and event-free survival (EFS) between patients with and without NAFLD. However, after restricting the target age to 10 years and older, 5-year EFS was significantly higher in patients with NAFLD than in those without (88.5 vs. 42.9%, respectively, P = 0.037). Similarly, 5-year cumulative incidence of relapse (CIR) was significantly lower in patients with NAFLD than in those without it (5-year CIR, 6.3 vs. 57.1%, respectively, P = 0.013).

CONCLUSION

Patients with NAFLD exhibit better outcomes including 5-year EFS and CIR. Further studies are necessary.

Identification and validation of suitable housekeeping genes for gene expression studies in BCR-ABL1 positive B-lineage acute lymphoblastic leukemia

BACKGROUND

The stability of the housekeeping gene (HKG) expression is an absolute prerequisite for accurate normalization of target gene expression in a quantitative real-time polymerase chain reaction (RQ-PCR). In RQ-PCR, the widely used normalization approach involves the standardization of target genes to the most stable HKG control genes. According to the recent literature, in different experimental conditions the HKGs exhibit either up or down-regulation and thus affecting the gene expression profiles of target genes which leads to erroneous results. This implies that it is very important to select the appropriate HKG and verify the expression stability of the HKG before quantification of the target gene.

METHODS AND RESULTS

The present study aims to analyze six different HKGs for their expression profiles and stability in BCR-ABL1 negative cases and validate them in BCR-ABL1 positive cases, detected by multiplex reverse transcribed polymerase chain reaction (RT-PCR). Six commonly used reference genes (GAPDH, ABL1, RNA18S, ACTB, GUSB, and EEF2) were selected in this study. RQ-PCR was performed on 24 BCR-ABL1 negative cases and the outcomes were validated on 24 BCR-ABL1 positive cases. RefFinder™, a web-based composite software was used to check the stability of HKG genes by different algorithms and comprehensive ranking of each HKG gene in BCR-ABL1 negative cases and finally validated in BCR-ABL1 positive cases.

CONCLUSIONS

It was found that RNA18S, ABL1 and GUSB are good stable HKG genes, which showed minimum variability in gene expression compared to GAPDH, EEF2, and ACTB, the most commonly used HKG.

De Novo MYC and BCL2 Double-hit B-Cell Precursor Acute Lymphoblastic Leukemia (BCP-ALL) in Pediatric and Young Adult Patients Associated With Poor Prognosis

MYC and BCL2 translocations in B-cell lymphomas are defined as "double-hit" associated with poor prognosis in adult patients. Such double-hit events are extremely rare in B-cell precursor acute lymphoblastic leukemia (BCP-ALL), especially in pediatric patients or young adults. This study is to investigate the clinical manifestation of de novo MYCyBCL2 double-hit BCP-ALL in young patients. Two pediatric and one young adult patients were identified after a retrospective data review and all without previous history of lymphoma. There were two females and one male aged 15, 18, and 24, respectively. All patients had an unremarkable medical history before presenting with extensive bone marrow and central nervous system involvement at diagnosis. Flow cytometry immunophenotypic analysis showed an immature B-cell immunophenotype (CD10+, CD19+, TdT+, surface Ig-) and immunohistochemistry showed high expression of MYC and BCL2 in all cases. All patients showed complex karyotypes associated with 8q24 abnormalities in the form of t(8;9)(q24;p13) or t(8;14)(q24;q32) and t(14;18)(q32;q21) and fluorescence in situ hybridization confirmed MYC and BCL2 rearrangements. Two patients died of refractory disease or disease progression 7 and 13 months after initial diagnosis, respectively, and the third patient was treated with protocol AALL0232 under the Children's Oncology Group study, achieved complete remission and remained in remission for 53 months at last follow-up. Our study showed that De novo MYCyBCL2 double-hit BCP-ALL is a rare disease that also occurs in pediatric and young adult patients and associated with complex karyotypes and poor prognosis. Younger patients may benefit from intensified chemotherapy.

Evaluation of multiplex ligation dependent probe amplification (MLPA) for identification of acute lymphoblastic leukemia with an intrachromosomal amplification of chromosome 21 (iAMP21) in a Brazilian population

Background

An intrachromosomal amplification of chromosome 21 (iAMP21) defines a unique subgroup of B-cell precursor acute lymphoblastic leukemia (BCP-ALL). The finding of three or more extra copies of the RUNX1 gene by fluorescence in situ hybridization (FISH) is internationally used to define an iAMP21. Genomic profiling of chromosome 21 has been suggested for assisting diagnostic case identification. Due to limitations of comparative genomic hybridization, in terms of a routine application as first line-screening tests we evaluated the multiplex ligation-dependent probe amplification (MLPA) SALSA P327_A1 and P327_B1 probe sets for detecting chromosome 21 copy number alterations in Brazilian childhood BCP-ALL.

Results

In 74 out of 368 patients gain of genetic material was detected. For data confirmation RUNX1 directed FISH was performed. Cells with ≥5 RUNX1 signals (n = 9) were considered as “true iAMP21” while <5 RUNX1 signals (n = 41) were counted as evidence for additional copies of intact chromosomes 21. All patients with an iAMP21 had high MLPA peak ratios (≥1.8), while the majority of patients with <5 RUNX1 presented low MLPA peak ratios (<1.8). Observed differences gained statistical strength by comparing probes located within the common region of amplification. Next, a principal component analysis was performed in order to illustrate distribution of cases according to their MLPA peak profile in two dimensions. Cases with an iAMP21 mostly clustered together, however additional cases with <5 RUNX1 signals or no available FISH data located in proximity.

Conclusions

MLPA qualified as a high throughput technique that could be employed in future studies for a critical comparison with data obtained by FISH, especially in cases where metaphase nuclei are not available. Taking submicroscopic aberrations into account examined by MLPA, cases exhibiting an “iAMP21 like” peak ratio profile but <5 RUNX1 signals should be considered as candidates for this chromosomal abnormality.

Electronic supplementary material

The online version of this article (doi:10.1186/s13039-015-0147-2) contains supplementary material, which is available to authorized users.