Fanconi anemia gene-associated germline predisposition in aplastic anemia and hematologic malignancies / 医学前沿

Whether Fanconi anemia (FA) heterozygotes are predisposed to bone marrow failure and hematologic neoplasm is a crucial but unsettled issue in cancer prevention and family consulting. We retrospectively analyzed rare possibly significant variations (PSVs) in the five most obligated FA genes, BRCA2, FANCA, FANCC, FANCD2, and FANCG, in 788 patients with aplastic anemia (AA) and hematologic malignancy. Sixty-eight variants were identified in 66 patients (8.38%). FANCA was the most frequently mutated gene (n = 29), followed by BRCA2 (n = 20). Compared with that of the ExAC East Asian dataset, the overall frequency of rare PSVs was higher in our cohort (P = 0.016). BRCA2 PSVs showed higher frequency in acute lymphocytic leukemia (P = 0.038), and FANCA PSVs were significantly enriched in AA and AML subgroups (P = 0.020; P = 0.008). FA-PSV-positive MDS/AML patients had a higher tumor mutation burden, higher rate of cytogenetic abnormalities, less epigenetic regulation, and fewer spliceosome gene mutations than those of FA-PSV-negative MDS/AML patients (P = 0.024, P = 0.029, P = 0.024, and P = 0.013). The overall PSV enrichment in our cohort suggests that heterozygous mutations of FA genes contribute to hematopoietic failure and leukemogenesis.

Identification of TCF3-ZNF384 fusion by transcriptome sequencing in B cell acute lymphoblastic leukemia and its laboratory and clinical characteristics / 中华医学遗传学杂志

OBJECTIVE@#To detect fusion gene with pathological significance in a patient with refractory and relapsed acute B cell lymphoblastic leukemia (B-ALL) and to explore its laboratory and clinical characteristics.@*METHODS@#Transcriptome sequencing was used to detect potential fusion transcripts. Other laboratory results and clinical data of the patient were also analyzed.@*RESULTS@#The patient was found to harbor TCF3 exon 17-ZNF384 exon 7 in-frame fusion transcript. The minimal residual disease (MRD) has remained positive after multiple chemotherapy protocols including CD19-, CD22- targeted chimeric antigen receptor T cells immunotherapy. The patient eventually achieved complete remission and sustained MRD negativity after allogeneic hemopoietic stem cell transplantation (allo-HSCT).@*CONCLUSION@#Transcriptome sequencing can effectively detect potential fusion genes with clinical significance in leukemia. TCF3-ZNF384 positive B-ALL has unique laboratory and clinical characteristics, may not well respond to chemotherapy and immunotherapy, and is more likely to relapse. Timely allo-HSCT treatment may help such patients to achieve long-term disease-free survival. TCF3-ZNF384 positive B-ALL is not uncommon in pediatric patients but has not been effectively identified.

Progress of gene expression and gene expression patterns in hematological malignancies / 白血病·淋巴瘤

Disorders of gene expression are closely related to the biological characteristics, treatment response, and prognosis of hematological malignancies. The rapidly-developing transcriptome sequencing and single-cell transcriptome sequencing technologies in recent years provide powerful tools for discovering marker genes and studying gene expression patterns related to disease diagnosis and treatment. This article reviews the related research progress in conjunction with reports at the 62nd American Society of Hematology (ASH) Annual Meeting.

Pathogenic infection spectrum revealed by metagenomics high-throughput next-generation sequencing in patients with hematological diseases after allogeneic hematopoietic stem cell transplantation / 白血病·淋巴瘤

Objective:To investigate the infection spectrum revealed by metagenomics high-throughput next-generation sequencing (mNGS), and to provide a reference for infection diagnosis after allogeneic hematopoietic stem cell transplantation (allo-HSCT).Methods:A total of 64 patients who developed systemic or local infection symptoms after allo-HSCT in Hebei Yanda Lu Daopei Hospital from January 2018 to November 2018 were enrolled. Gene sequences of pathogenic microorganisms in blood, cerebrospinal fluid and bronchoalveolar fluid specimens were detected by using mNGS. The pathogenic microorganisms or suspected pathogens were determined based on the clinical manifestations of patients.Results:There were 97 samples of mNGS detection for 64 patients who underwent allo-HSCT. The most common gram-positive bacteria were staphylococcus haemolyticus (19 times) and staphylococcus (14 times), and the most common gram-negative bacterium was acinetobacter baumannii (8 times). The most common viruses were cytomegalovirus, EB virus and Torque teno virus (35, 22 and 23 times, respectively), and the most common fungi were malassezia globus (14 times) and candida parapsilosis (8 times). There were 3 mycobacterium tuberculosis complexes detected in 3 patients with acute myeloid leukemia who received allo-HSCT. Mycoplasma orale was detected in one patient's sputum, and none parasite was detected.Conclusion:mNGS can comprehensively reveal the infection spectrum of hematologic diseases after allo-HSCT, especially for pathogenic microorganisms that are rare or difficult to cultivate, and it can effectively help the diagnosis of clinically infectious pathogens.

Application of metagenomics next-generation sequencing in monitoring Legionella pneumophila infection after allogeneic hematopoietic stem cell transplantation / 白血病·淋巴瘤

Objective@#To investigate the application of metagenomic next-generation sequencing (mNGS) in detection of the rare or difficult-to-cultivate pathogens.@*Methods@#One patient with acute lymphoblastic leukemia who went through allogeneic hematopoietic stem cell transplantation (allo-HSCT) developed symptoms of infection after transplantation. Conventional microbial culture, polymerase chain reaction (PCR), and mNGS combined with biological information analysis were performed with plasma and cerebrospinal fluid samples, the anti-infective treatment was adjusted according to the test results, and the efficacy was assessed.@*Results@#No suspected pathogens were detected by microbial culture and PCR in the cerebrospinal fluid and plasma samples since the patient developed infection symptoms. However, Legionella pneumophila was analyzed by mNGS in the cerebrospinal fluid specimen on day 23 after allo-HSCT (reads count: 19 655), and it was considered as the principal pathogen after comprehensively evaluating the patient's clinical manifestations and the test results. Then the antimicrobial treatments were adjusted according to the patient's clinical manifestations and laboratory test results, and the number of gene sequences of Legionella pneumophila was monitored by mNGS method. Azithromycin, tigecycline, and other antibiotics effective for Legionella pneumophila were used after detecting this pathogen. A total of 15 mNGS analysis were performed during the 5-month period, and the highest number of Legionella pneumophila sequences monitored in the cerebrospinal fluid was 2 226, the lowest was 253 and eventually turned negative. The clinical symptoms and treatment outcomes were consistent with the mNGS monitoring results.@*Conclusions@#The mNGS technology has significant value in detection of the rare and difficult-to-cultivate pathogens. The mNGS technology provides a valuable supplement to microbial culture and PCR methods.

Application progress of transcriptome sequencing in hematological malignancies / 白血病·淋巴瘤

Transcriptome sequencing (RNA-seq) has unique advantages in analyzing gene fusion, splicing mutations, and gene expression profiles. Single-cell RNA-seq provides powerful tools to reveal cellular heterogeneity in normal and tumor tissues. With the widespread application of high-throughput gene sequencing technology and the rapid reduction in cost, RNA-seq is increasingly used in hematological malignancies research. This article introduces the related research progress in conjunction with reports at the 61st American Society of Hematology Annual Meeting.

Mixed鄄phenotypic acute leukemia with SET鄄NUP214 fusion gene positive and extramedullary infiltration: report of one case and review of literature / 白血病·淋巴瘤

Objective To investigate the clinical and molecular biological characteristics of mixed_phenotypic acute leukemia (MPAL) with SET_NUP214 fusion gene positive and extramedullary infiltration. Methods The clinical characteristics, diagnosis and treatment of one MPAL patient with SET_NUP214 and extramedullary infiltration who was admitted to Hebei Yanda Ludaopei Hospital in November 2017 were analyzed, and the literature was reviewed. Results The patient was diagnosed as MPAL with extramedullary infiltration. Gene detection found SET exon7_NUP214 exon17 fusion positive accompanied with PHF6, SRSF2 and NRAS mutations. After intensive chemotherapy, the patient achieved complete remission, and then received hematopoietic stem cell transplantation (HSCT), followed by early extramedullary relapse after transplantation, and achieved secondary remission after consolidation chemotherapy. Conclusions MPAL with SET_NUP214 fusion gene positive and extramedullary infiltration has a poor prognosis, and it is easy to relapse. Currently, HSCT is the best available treatment strategy for such patients.

Progress of genomic analysis and its clinical application in hematological diseases / 白血病·淋巴瘤

With the rapid decline of cost and the increase of analysis ability, the significant increase of genomics analysis in the research and application of human diseases has brought revolutionary progress in medical test from "target detection" to "target analysis". Based on the recent research progress and reports in the 59th American Society of Hematology Annual Meeting, this paper introduces application prospect of genomic analysis in hematological diseases.