Fanconi anaemia presenting as acute myeloid leukaemia and myelodysplastic syndrome in adulthood: a family report on co-occurring FANCC and CHEK2 mutations

PML mutation and familial pediatric acute lymphoblastic leukemia: A case report

Hereditary factors contribute to the pathogenesis of pediatric leukemia. However, few studies have reported gene mutation pathopoeias. This paper reports genetic mutations associated with hereditary acute lymphoblastic leukemia. We reported a case of siblings diagnosed with acute lymphoblastic leukemia when aged 3 and 7 years, both siblings are alive after chemotherapy, and whole exome sequencing analysis was performed on the siblings and their parents. It was observed that both siblings had diheterozygous mutations in PML gene (PML, NM_033250, exon7, c.2170A>G, p.S724G; PML, NM_033250, exon7, c.2195G>T, p.G732V), and their parents had heterozygous mutations in one mutation site of PML gene, respectively, suggesting that the diheterozygous mutations of PML gene might be causal genetic genes for the occurrence of acute lymphoblastic leukemia.

Germline Variants and Characteristic Features of Hereditary Hematological Malignancy Syndrome

Due to the proliferation of genetic testing, pathogenic germline variants predisposing to hereditary hematological malignancy syndrome (HHMS) have been identified in an increasing number of genes. Consequently, the field of HHMS is gaining recognition among clinicians and scientists worldwide. Patients with germline genetic abnormalities often have poor outcomes and are candidates for allogeneic hematopoietic stem cell transplantation (HSCT). However, HSCT using blood from a related donor should be carefully considered because of the risk that the patient may inherit a pathogenic variant. At present, we now face the challenge of incorporating these advances into clinical practice for patients with myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML) and optimizing the management and surveillance of patients and asymptomatic carriers, with the limitation that evidence-based guidelines are often inadequate. The 2016 revision of the WHO classification added a new section on myeloid malignant neoplasms, including MDS and AML with germline predisposition. The main syndromes can be classified into three groups. Those without pre-existing disease or organ dysfunction; DDX41, TP53, CEBPA, those with pre-existing platelet disorders; ANKRD26, ETV6, RUNX1, and those with other organ dysfunctions; SAMD9/SAMD9L, GATA2, and inherited bone marrow failure syndromes. In this review, we will outline the role of the genes involved in HHMS in order to clarify our understanding of HHMS.

Efficacy of Dabrafenib and Trametinib in a Patient with Squamous-Cell Carcinoma, with Mutation p.D594G in BRAF and p.R461* in NF1 Genes-A Case Report with Literature Review

The 3rd class of BRAF (B-Raf Proto-Oncogene, Serine/Threonine Kinase) variants including G466, D594, and A581 mutations cause kinase death or impaired kinase activity. It is unlikely that RAF (Raf Proto-Oncogene, Serine/Threonine Kinase) inhibitors suppress ERK (Extracellular Signal-Regulated Kinase) signaling in class 3 mutant-driven tumors due to the fact that they preferentially inhibit activated BRAF V600 mutants. However, there are suggestions that class 3 mutations are still associated with enhanced RAS/MAPK (RAS Proto-Oncogene, GTPase/Mitogen-Activated Protein Kinase) activation, potentially due to other mechanisms such as the activation of growth factor signaling or concurrent MAPK pathway mutations, e.g., RAS or NF1 (Neurofibromin 1). A 75-year-old male patient with squamous-cell cancer (SqCC) of the lung and with metastases to the kidney and mediastinal lymph nodes received chemoimmunotherapy (expression of Programmed Cell Death 1 Ligand 1 (PD-L1) on 2% of tumor cells). The chemotherapy was limited due to the accompanying myelodysplastic syndrome (MDS), and pembrolizumab monotherapy was continued for up to seven cycles. At the time of progression, next-generation sequencing was performed and a c.1781A>G (p.Asp594Gly) mutation in the BRAF gene, a c.1381C>T (p.Arg461Ter) mutation in the NF1 gene, and a c.37C>T (p.Gln13Ter) mutation in the FANCC gene were identified. Combined therapy with BRAF (dabrafenib) and MEK (trametinib) inhibitors was used, which resulted in the achievement of partial remission of the primary lesion and lung nodules and the stabilization of metastatic lesions in the kidney and bones. The therapy was discontinued after five months due to myelosuppression associated with MDS. The molecular background was decisive for the patient’s fate. NSCLC patients with non-V600 mutations in the BRAF gene rarely respond to anti-BRAF and anti-MEK therapy. The achieved effectiveness of the treatment could be related to a mutation in the NF1 tumor suppressor gene. The loss of NF1 function causes the excessive activation of KRAS and overactivity of the signaling pathway containing BRAF and MEK, which were the targets of the therapy. Moreover, the mutation in the FANCC gene was probably related to MDS development. The NGS technique was crucial for the qualification to treatment and the prediction of the NSCLC course in our patient. The mutations in two genes—the BRAF oncogene and the NF1 tumor suppressor gene—were the reason for the use of dabrafenib and trametinib treatment. The patients achieved short-term disease stabilization. This proved that coexisting mutations in these genes affect the disease course and treatment efficacy.

FANCC deficiency mediates microglial pyroptosis and secondary neuronal apoptosis in spinal cord contusion

Background

Traumatic spinal cord injury (SCI)-induced neuroinflammation results in secondary neurological destruction and functional disorder. Previous findings showed that microglial pyroptosis plays a crucial role in neuroinflammation. Thus, it is necessary to conduct a comprehensive investigation of the mechanisms associated with post-SCI microglial pyroptosis. The Fanconi Anemia Group C complementation group gene (FANCC) has been previously reported to have an anti-inflammation effect; however, whether it can regulate microglial pyroptosis remains unknown. Therefore, we probed the mechanism associated with FANCC-mediated microglial pyroptosis and neuroinflammation in vitro and in vivo in SCI mice.

Methods

Microglial pyroptosis was assessed by western blotting (WB) and immunofluorescence (IF), whereas microglial-induced neuroinflammation was evaluated by WB, Enzyme-linked immunosorbent assays and IF. Besides, flow cytometry, TdT-mediated dUTP Nick-End Labeling staining and WB were employed to examine the level of neuronal apoptosis. Morphological changes in neurons were assessed by hematoxylin–eosin and Luxol Fast Blue staining. Finally, locomotor function rehabilitation was analyzed using the Basso Mouse Scale and Louisville Swim Scale.

Results

Overexpression of FANCC suppressed microglial pyroptosis via inhibiting p38/NLRP3 expression, which in turn reduced neuronal apoptosis. By contrast, knockdown of FANCC increased the degree of neuronal apoptosis by aggravating microglial pyroptosis. Besides, increased glial scar formation, severe myelin sheath destruction and poor axon outgrowth were observed in the mice transfected with short hairpin RNA of FANCC post SCI, which caused reduced locomotor function recovery.

Conclusions

Taken together, a previously unknown role of FANCC was identified in SCI, where its deficiency led to microglia pyroptosis, neuronal apoptosis and neurological damage. Mechanistically, FANCC mediated microglia pyroptosis and the inflammatory response via regulating the p38/NLRP3 pathway.

Germline CHEK2 and ATM Variants in Myeloid and Other Hematopoietic Malignancies

PURPOSE OF REVIEW

An intact DNA damage response is crucial to preventing cancer development, including in myeloid and lymphoid malignancies. Deficiencies in the homologous recombination (HR) pathway can lead to defective DNA damage responses, and this can occur through inherited germline mutations in HR pathway genes, such as CHEK2 and ATM. We now understand that germline mutations can be identified frequently (~ 5-10%) in patients with myeloid and lymphoid malignancies, and among the most common of these are CHEK2 and ATM. We review the role that deleterious germline CHEK2 and ATM variants play in the development of hematopoietic malignancies, and how this influences clinical practice, including cancer screening, hematopoietic stem cell transplantation, and therapy choice.

RECENT FINDINGS

In recent large cohorts of patients diagnosed with myeloid or lymphoid malignancies, deleterious germline loss of function variants in CHEK2 and ATM are among the most common identified. Germline CHEK2 variants predispose to a range of myeloid malignancies, most prominently myeloproliferative neoplasms and myelodysplastic syndromes (odds ratio range: 2.1-12.3), and chronic lymphocytic leukemia (odds ratio 14.83). Deleterious germline ATM variants have been shown to predispose to chronic lymphocytic leukemia (odds ratio range: 1.7-10.1), although additional studies are needed to demonstrate the risk they confer for myeloid malignancies. Early studies suggest there may also be associations between deleterious germline CHEK2 and ATM variants and development of clonal hematopoiesis. Identifying CHEK2 and ATM variants is crucial for the optimal management of patients and families affected by hematopoietic malignancies. OPENING CLINICAL CASE: "A 45 year-old woman presents to your clinic with a history of triple-negative breast cancer diagnosed five years ago, treated with surgery, radiation, and chemotherapy. About six months ago, she developed cervical lymphadenopathy, and a biopsy demonstrated small lymphocytic leukemia. Peripheral blood shows a small population of lymphocytes with a chronic lymphocytic leukemia immunophenotype, and FISH demonstrates a complex karyotype: gain of one to two copies of IGH and FGFR3; gain of two copies of CDKN2C at 1p32.3; gain of two copies of CKS1B at 1q21; tetrasomy for chromosome 3; trisomy and tetrasomy for chromosome 7; tetrasomy for chromosome 9; tetrasomy for chromosome 12; gain of one to two copies of ATM at 11q22.3; deletion of chromosome 13 deletion positive; gain of one to two copies of TP53 at 17p13.1). Given her history of two cancers, you arrange for germline genetic testing using DNA from cultured skin fibroblasts, which demonstrates pathogenic variants in ATM [c.1898 + 2 T > G] and CHEK2 [p.T367Metfs]. Her family history is significant for multiple cancers. (Fig. 1)." Fig. 1 Representative pedigree from a patient with germline pathogenic ATM and CHEK2 variants who was affected by early onset breast cancer and chronic lymphocytic leukemia. Arrow indicates proband. Colors indicate cancer type/disease: purple, breast cancer; blue, lymphoma; brown, melanoma; yellow, colon cancer; and green, autoimmune disease.

Next-generation sequencing in hypoplastic bone marrow failure: What difference does it make?

Hypoplastic bone marrow failure is a diagnostic feature of multiple haematological disorders, which also share a substantial overlap of clinical symptoms. Hence, discrimination of underlying disorders in patients presenting with hypoplastic bone marrow failure remains a major challenge in the clinic. Recent next-generation sequencing (NGS) studies have broadened our understanding of the varying molecular mechanisms and advanced diagnostics of disorders exhibiting hypoplastic bone marrow failure. In this article, we present a literature review of NGS studies of haematological disorders associated with hypoplastic bone marrow failure and highlight the relevance of NGS for improved clinical diagnostics and decision-making.