Genomic signatures and prognosis of advanced stage Chinese pediatric T cell lymphoblastic lymphoma by whole exome sequencing.

Objective: To investigate the genomic signatures and prognosis of advanced-stage T cell lymphoblastic lymphoma (T-LBL) and to examine the relationship between T-LBL and T cell acute lymphoblastic leukemia (T-ALL). Methods: 35 Chinese T-LBL children with stage III or IV disease were recruited for this study. They were treated with combination chemotherapy and whole exome sequencing. The relationship of the clinical features, prognosis and specific gene mutations was researched. Gene chips of T-LBL and T-ALL were downloaded from a database, and differential gene expression was analyzed. Results: Germline causal gene mutations (CARS or MAP2K2) were detected in 2 patients; 3.06 ± 2.21 somatic causal gene mutations were identified in the 35 patients, and somatic mutations were observed in the NOTCH1, FBXW7, PHF6 and JAK3 genes. NOTCH1 mutations were significantly associated with FBXW7 mutations, and the age at diagnosis of patients with NOTCH1-FBXW7 mutations was less than that of patients without such mutations (P < 0.05). 32 patients achieved complete remission (CR), and 14 and 18 patients were classified into the intermediate risk (IR) group and high risk (HR) group. During a median follow-up of 44 months, 3 patients relapsed. Three-year prospective event free survival (pEFS) was 82.286%, and no significant differences of pEFS were found for different sexes, ages, or statuses of NOTCH1-FBXW7 mutations, (P > 0.05); however, the mean survival time of the IR group was longer than that of the HR group (P < 0.05). Differential expression of genes in the T-LBL and/or T-ALL datasets was analyzed using the R package limma, and 1/3 of the differentially expressed genes were found in both the T-ALL and T-LBL datasets. High expression of PI3K-Akt signal pathway genes and the USP34 gene was found in the T-LBL dataset. Conclusion: Although T-ALL and T-LBL both originate from precursor T-cells and are considered different manifestations of the same disease and the outcome of T-LBL is favorable when using T-ALL-based chemotherapy, there are differences in the gene distribution between T-LBL and T-ALL. It seems that the PI3K-Akt signaling pathway and the USP34 gene play important roles in T-LBL, but medicines targeting the USP34 gene or the PI3K-Akt pathway may be invalid.

Poor treatment responses were related to poor outcomes in pediatric B cell acute lymphoblastic leukemia with KMT2A rearrangements.

BACKGROUND: The KMT2A gene, formerly named the MLL gene, is rearranged (KMT2Ar) in 70-75% of infants, 5-6% of children and 10-15% of adult patients with B cell acute lymphoblastic leukemia (B-ALL). The outcome after chemotherapy of pediatric cases remains poor, and only a few studies have investigated the clinical and laboratory features, treatment response and prognosis in Chinese populations. METHODS: A total of 48 B-ALL children with KMT2Ar were enrolled in the study, and clinical and laboratory data were collected and analyzed by age group. The relationship between prognosis and traditional risk factors and treatment response was investigated for these patients who received chemotherapy. RESULTS: The 48 enrolled patients included 28 males and 20 females; 18 (37.50%) or 30 (62.50%) patients were an age of < 12 m (infant B-ALL) or of > 12 m at onset. An initial WBC count of 300 × 109/L was detected in 7 (14.58%) patients; testicular leukemia (TL) or central nervous system involvement was found in 5 (10.41%) or 3 (6.25%) patients, respectively. Statistical differences were not found in the age groups of sex or initial WBC count, whereas TL was more common in the infant group (P < 0.05). 11q23 was detected in 18 patients; KMT2Ar was detected in 46 (95.83%) or 45 (93.75%) patients by FISH or multiplex RT-PCR technology, respectively; RNA-seq data were obtained for 18 patients, and 3 patients with uncommon KMT2Ar were identified. KMT2A-AFF1, KMT2A-MLLT3 and KMT2A-MLLT1 were the most common transcripts. Statistical differences were not found in treatment response by age groups, including dexamethasone induction, bone marrow (BM) smear status and minimal residual disease (MRD) level at different time points (TP), treatment-related mortality (TRM), or complete remission (CR) rate (P > 0.05); MRD levels monitored by FCM or PCR were unequal at the same TP. Four patients died of treatment, and TRM was 8.33%; 40 patients achieved CR, and the CR rate for the cohort was 83.33%. Seven patients quit, 15 patients relapsed, and the 5 yr cumulative relapse rate was 59.16 ± 9.16%; the 5 yr prospective EFS (pEFS) for patients who were included or excluded from the TRM group was 36.86 ± 8.48% or 40.84 ± 9.16%, respectively. Multivariate analysis for prognosis and hazard ratio was performed for 37 patients without TRM and revealed that an initial WBC count of > 300 × 109/L and a positive level of FCM-MRD were strongly related to a poor outcome for B-ALL patients with KMT2Ar (P < 0.05).

Pediatric acute myeloid leukemia patients with i(17)(q10) mimicking acute promyelocytic leukemia: Two case reports.

BACKGROUND: Chromosome i(17)(q10) abnormality is mainly associated with chronic myeloid leukemia (CML), myelodysplastic syndrome/myeloproliferative tumors (MDS/MPD), and acute myeloid leukemia (AML). The role of i(17)(q10) in AML is still unknown, the differences between AML and acute promyelocytic leukemia (APL)-like AML with i(17)(q10) need more research. This study aimed to investigate the clinical characteristics and laboratory evidence of 2 AML cases with i(17)(q10), similar to APL phenotype. CASE SUMMARY: Both pediatric patients were males; case 1 had newly diagnosed AML, and case 2 showed relapsed tumor after 1 year of drug withdrawal. Bone marrow cell morphology, chromosome karyotype analysis, Fully-instrumented submersible housing test, immunological assays, molecular biological methods, and blood tumor panoramic gene test were performed. All-trans retinoic acid (ATRA) combined with arsenic acid (As2O3) were used in the first course of treatment. Bone marrow was dominated by abnormal promyelocytic granulocytes. Karyotype test revealed i(17)(q10) isochromosome. Immunological phenotype mainly included positive expressions of CD9, CD13, CD33, and CD38. Case 1 suffered intracranial hemorrhage after re-chemotherapy and died on D162. For case 2, on D145 and D265, bone marrow promyelocytic granulocytes accounted for 2%. Flow cytometric residual lesion detection showed no abnormal immunophenotype cells. The copy number of WT1 gene in two cases were 1087 and 1010, respectively, and the expression rates were 55.29% and 59.5%, respectively. CONCLUSION: ATRA, As2O3, and chemotherapy may be ineffective in treating APL-like AML with i(17)(q10) but without t(15;17) and PML-RARA fusion gene.

The long-term outcome and risk factors for precursor B cell acute lymphoblastic leukemia without specific fusion genes in Chinese children: experiences from multiple centers.

Specific fusion genes play important roles as risk factors for strategic treatment in pediatric B-cell acute lymphoblastic leukemia (B-ALL), and the risk factors in patients without common fusion genes have not been well demonstrated. We collected and analyzed clinical and laboratory findings, treatment responses and outcomes in B-ALL patients without specific fusion genes. Whole-exome sequencing (WES) and/or RNA sequencing (RNAseq) data from bone marrow relapsed patients were also analyzed. 283 patients were enrolled in the study. Traditional elements and treatment responses at different time points (TPs) were evaluated to classify risk groups and adjust the treatment strategy. Treatment-related mortality was found in 11 (3.89%) patients, 49 (17.31%) patients relapsed, and the ten-year prospective event-free survival (pEFS) was 78.2±2.5%. Univariate analysis revealed that significant differences were not found in the pEFS of traditional risk factors, including sex, age, WBC count or chromosome status; good responses of BM smears at TP1 and minimal residual disease (MRD) levels at TP2 and TP3 were strongly associated with prolonged pEFS. Compared with the IR or the HR group, patients in the SR group presented with longer pEFS and a lower relapse rate. Multivariable analysis of outcomes and hazard ratios revealed that a positive MRD level was a key risk factor. WES or RNAseq was performed for BM relapse patients, and adverse and unreported genetic abnormalities were discovered. Favorable outcomes were acquired in the cohort. The study results showed that traditional risk factors and poor prednisone response were overcome by modified chemotherapy, and a positive MRD level was a key risk factor in these patients. NGS is needed to discover more risk-related molecular abnormalities.

Case Report: Genetic and Clinical Features of Maternal Uniparental Isodisomy-Induced Thiamine-Responsive Megaloblastic Anemia Syndrome.

Background: Thiamine-responsive megaloblastic anemia syndrome (TRMA) is a rare autosomal recessive hereditary disease due to mutations in SLC19A2. Some cases show familial inheritance. Case report: A female patient (from a gravida 1, para 1 mother) of 3.5 years of age was admitted to the Pediatric Hematology Department of Xianyang Caihong Hospital in June 2019. The patient had severe anemia, acupoint-size bleeding spots, and a few ecchymoses all over her body, as well as astigmatism and hyperopia. Hearing was normal. The patient had diabetes. Bone marrow biopsy suggested a myelodysplastic syndrome. The patient had a c.515G>A (p.G172D) homozygous mutation of SLC19A2 (NM_006996), indicating TRMA. Genetic testing revealed that the two alleles were inherited from her mother alone due to maternal uniparental isodisomy (UPD). The patient was treated with thiamine and a subcutaneous injection of insulin. The patient recovered well and was discharged. She continued thiamine and insulin at the same dose and was followed once a month. The last follow-up on September 15, 2020, showed no anemia or bleeding. She had a sound hearing and normal blood routine and fasting glucose levels. Hyperopia and astigmatism did not improve. Conclusion: The patient had TRMA induced by the c.515G>A (p.G172D) homozygous mutation of SLC19A2 inherited through maternal UPD. The genetic diagnosis of TRMA is of significance for guiding clinical treatment. Early treatment with exogenous thiamine can improve some of the clinical features of TRMA.

Clinical characterization and prognosis of T cell acute lymphoblastic leukemia with high CRLF2 gene expression in children.

It has been reported that overexpression of the CRLF2 gene is associated with poor outcomes in pediatric B cell acute lymphoblastic leukemia (B-ALL), but the incidence rates, clinical characteristics and outcomes of CRLF2 gene overexpression in pediatric T cell ALL (T-ALL) have not been systematically analyzed. In this study, CRLF2 mRNA expression levels and clinical and laboratory parameters in 63 pediatric T-ALL patients were detected at the Children's Hospital of Chongqing Medical University and Children's Hospital of Xianyang between February 2015 and June 2018. The patients were treated according to the modified St. Jude TXV ALL protocol, and early treatment responses (bone marrow smear and MRD level) and prognoses in the enrolled patients were assessed. CRLF2 overexpression was detected in 21/63 (33.33%) patients. Statistical differences were not found for clinical or laboratory parameters (including sex, age, initial WBC count, incidence mediastinal involvement, abnormal karyotype and fusion genes) between patients with high CRLF2 expression and patients with low expression of CRLF2 (P>0.05). One patient died of tumor lysis syndrome and renal failure, and the treatment response was monitored on day 19 (TP1) of remission in 62 patients. One patient quit treatment because of family decisions, and 61 patients underwent treatment response evaluation on day 46 (TP2) of remission. Significant differences were not found between patients with high CRLF2 expression and patients with low CRLF2 expression in terms of the treatment responses at TP1 or TP2 (P>0.05). Following October 2018, 12 patients among the 61 evaluable patients relapsed (relapse rate: 19.67%), 3 patients died from chemotherapy, and the treatment-related mortality (TRM) rate was 4.92%. Secondary tumors occurred in 1 patient. The 3-year prospective EFS rate was 54.1±11.2% and 77.7±6.6% for the 61 evaluable patients and 58 patients without TRM. Patients with low CRLF2 expression had longer EFS durations than patients with high CRLF2 expression (61 evaluable patients: 35.91± 2.38 months vs 23.43± 2.57 months; 58 patients without TRM: 37.86± 2.08 months vs 24.55±2.43 months, P<0.05). CRLF2 expression levels were also monitored in 13 patients at TP1 and TP2, and the MRD level did not vary with the CRLF2 expression level. Our data suggest that clinical features, laboratory findings and treatment responses in the pediatric T-ALL population do not vary based on the overexpression of CRLF2 but that CRLF2 overexpression can contribute to a high risk of relapse in pediatric T-ALL. Thus, CRLF2 expression levels should not be used as biomarkers for monitoring MRD.

Study on clinical characteristics and follow-up visit of acquired aplastic anemia associated with parvovirus B19 infection.

OBJECTIVE: To investigate clinical characteristics of parvovirus (B19) related aplastic anemia (AA). METHODS: Of the 28 children with AA included in this study, 24 were treated routinely and received planned follow-up; 15 were subject to B19-DNA re-examination during the treatment and 8 underwent examination for B19-IgM and B19-IgG. Another 39 initially identified AA children were enrolled as the controls and received the treatment same as the above-mentioned group. RESULTS: There were more patients aged 5-8 y in the B19 infection group than the control group (P < 0.05). The course of AA in the B19 infection group was less than 2 mo and the serious aplastic anemia (SAA) and very serious aplastic anemia (VSAA) were more frequently observed in this group than the controls (P < 0.05). The overall efficacy of the treatments in the B19 infection group was more dismal than that in the controls (P < 0.05). Among 15 patients who were subjected to B19-DNA re-examination, negative findings were found in 6 patients with chronic aplastic anemia (CAA); the B19-DNA was persistently positive in 2 of the SAA and 5 VSAA patients. IgM and IgG were respectively detected in 3 and 2 patients out of the 8 children who received antibody examination. CONCLUSIONS: Parvovirus B19 infection contributes to the generation of AA, particularly in children aged 5-8 y. The AA induced may be mainly classified as serious and very serious type, with a course of disease less than 2 mo. Patients can be saved if B19-DNA is eliminated and the antibody is produced.

Hemogram and bone marrow morphology in children with chronic aplastic anemia and myelodysplastic syndrome.

BACKGROUND: Aplastic anemia (AA) and myelodysplastic syndrome (MDS) are both acquired disorders in which bone marrow fails to produce or release sufficient blood cells. Anemia, infections and thrombocytopenia are common signs of such diseases. Clinically, it is difficult to distinguish chronic aplastic anemia (CAA) from MDS, especially from MDS without splenomegaly. As prognosis and treatment of AA and MDS are different, it is extremely important to make a differential diagnosis for the two diseases. METHODS: The medical records of 31 patients with CAA and 17 patients with MDS were retrospectively reviewed. Hemogram, bone marrow smear and biopsy for those patients were analyzed. RESULTS: The mean counts of monocytes and platelets in the peripheral blood of the CAA patients were significantly lower than those of the MDS patients. Bone marrow smear showed a reduction of cellularity in CAA patients. The mean counts of myeloblasts+promyelocytes, myeloblasts+proerythroblasts, and megakaryocytes in the bone marrow of CAA patients were markedly lower than those in MDS patients. But the mean lymphocyte count was reversed. Bone marrow cells showed morphological abnormalities in MDS. Hematopoietic tissue in the bone marrow biopsy decreased obviously in more than 96% of the patients with CAA. Adipose tissue in the bone marrow of CAA patients increased obviously. A reduction or deficiency (<2 cell/piece) of megakaryocytes was noted in 28 patients with CAA. Fibrous tissue in the bone marrow was detected in 5 patients with CAA. Bone marrow biopsy results showed hypercellular changes in 12 MDS patients. Ten patients showed aggregated erythroblasts which were in the same stage of development, and 15 patients had abnormal localization of immature precursors (ALIP). CONCLUSIONS: Blood cell counts can be decreased in addition to the reduction of cellularity in the bone marrow without dyshematopoiesis in CAA patients. Peripheral blood monocytes, fibrous tissue and cellularity in bone marrow are increased in MDS. Dyshematopoiesis and ALIP may appear characteristically in the children with MDS. Histology of bone marrow is important in the differential diagnosis of MDS and CAA.