Fanconi anemia and the development of leukemia

BRCA2 C-terminal clamp restructures RAD51 dimers to bind B-DNA for replication fork stability

Tumor suppressor protein BRCA2 acts with RAD51 in replication-fork protection (FP) and homology-directed DNA break repair (HDR). Critical for cancer etiology and therapy resistance, BRCA2 C-terminus was thought to stabilize RAD51-filaments after they assemble on single-stranded (ss)DNA. Here we determined the detailed crystal structure for BRCA2 C-terminal interaction-domain (TR2i) with ATP-bound RAD51 prior to DNA binding. In contrast to recombinogenic RAD51-filaments comprising extended ATP-bound RAD51 dimers, TR2i unexpectedly reshapes ATP-RAD51 into a unique dimer conformation accommodating double-stranded B-DNA binding unsuited for HDR initiation. Structural, biochemical, and molecular results with interface-guided mutations uncover TR2i's FP mechanism. Proline-driven secondary-structure stabilizes residue triads and spans the RAD51 dimer engaging pivotal interactions of RAD51 M210 and BRCA2 S3291/P3292, the cyclin-dependent kinase (CDK) phosphorylation site that toggles between FP during S-phase and HDR in G2. TR2i evidently acts as an allosteric clamp switching RAD51 from ssDNA to double-stranded and B-DNA binding enforcing FP over HDR.

Longitudinal clinical manifestations of Fanconi anemia: A systematized review

Fanconi anemia (FA) is a rare and complex inherited genetic disorder characterized by impaired DNA repair mechanisms leading to genomic instability. Individuals with FA have increased susceptibility to congenital anomalies, progressive bone marrow failure, leukemia and malignant tumors, endocrinopathies and other medical issues. In recent decades, steadily improved approaches to hematopoietic cell transplantation (HCT), the only proven curative therapy for the hematologic manifestations of FA, have significantly increased the life expectancy of affected individuals, illuminating the need to understand the long-term consequences and multi-organ ramifications. Utilizing a systematized review approach with narrative synthesis of each primary issue and organ system, we shed light on the challenges and opportunities for optimizing the care and quality of life for individuals with FA and identify knowledge gaps informing future research directions.

Cancer Precursor Syndromes and Their Detection in the Head and Neck

This article explores the multifaceted landscape of oral cancer precursor syndromes. Hereditary disorders like dyskeratosis congenita and Fanconi anemia increase the risk of malignancy. Oral potentially malignant disorders, notably leukoplakia, are discussed as precursors influenced by genetic and immunologic facets. Molecular insights delve into genetic mutations, allelic imbalances, and immune modulation as key players in precancerous progression, suggesting potential therapeutic targets. The article navigates the controversial terrain of management strategies of leukoplakia, encompassing surgical resection, chemoprevention, and immune modulation, while emphasizing the ongoing challenges in developing effective, evidence-based preventive approaches.

Role of the mesenchymal stromal cells in bone marrow failure of Fanconi Anemia patients

Introduction

Fanconi anemia (FA) is an inherited disorder characterized by bone marrow failure, congenital malformations, and predisposition to malignancies. Alterations in hematopoietic stem cells (HSC) have been reported, but little is known regarding the bone marrow (BM) stroma. Thus, the characterization of Mesenchymal Stromal Cells (MSC) would help to elucidate their involvement in the BM failure.

Methods

We characterized MSCs of 28 FA patients (FA-MSC) before and after treatment (hematopoietic stem cell transplantation, HSCT; or gene therapy, GT). Phenotypic and functional properties were analyzed and compared with MSCs expanded from 26 healthy donors (HD-MSCs). FA-MSCs were genetically characterized through, mitomycin C-test and chimerism analysis. Furthermore, RNA-seq profiling was used to identify dysregulated metabolic pathways.

Results

Overall, FA-MSC had the same phenotypic and functional characteristics as HD-MSC. Of note, MSC-GT had a lower clonogenic efficiency. These findings were not confirmed in the whole FA patients' cohort. Transcriptomic profiling identified dysregulation in HSC self-maintenance pathways in FA-MSC (HOX), and was confirmed by real-time quantitative polymerase chain reaction (RT-qPCR).

Discussion

Our study provides a comprehensive characterization of FA-MSCs, including for the first time MSC-GT and constitutes the largest series published to date. Interestingly, transcript profiling revealed dysregulation of metabolic pathways related to HSC self-maintenance. Taken together, our results or findings provide new insights into the pathophysiology of the disease, although whether these niche defects are involved in the hematopoietic defects seen of FA deserves further investigation.

TMT-based proteomics analysis of the blood enriching mechanism of the total Tannins of Gei Herba in mice

Lanbuzheng (LBZ) is the traditional seedling medicine in Guizhou, which has the effect of tonifying blood. It has been found that the main active ingredient is tannin, however, the blood-replenishing effect of tannin and its mechanism are still unclear. The study was to explore the mechanisms underlying the therapeutic effects of the total Tannins of Lanbuzheng (LBZT) against anemia in mice. Anemia mice was induced by cyclophosphamide, the effect of LBZT against anemia was determined by analyzing peripheral blood and evaluating organs indexes. Tandem mass tag (TMT)-based quantitative proteomics technology coupled with bioinformatics analysis was then used to identify differentially expressed proteins (DEPs) in spleen. Compared to the model, number of RBCs, PLTs and WBCs, HCT ratio and HGB content were increased, the indexes of thymus, spleen and liver were also increased, after LBZT intervention. A total of 377 DEPs were identified in LBZT group, of which 206 DEPs were significantly up-regulated and 171 DEPs were significantly down-regulated. Bioinformatics analysis showed that hematopoietic function has been restored by activating the complement and coagulation cascade signaling pathways. Results suggest that LBZT exerts it therapeutic effects against anemia by regulating complement and coagulation cascade signaling pathways and provides scientific basis for further mechanistic studies for LBZT.

Characteristic phenotypes of ADH5/ALDH2 deficiency during childhood

ADH5/ALDH2 deficiency is a rare inherited syndrome characterized by short stature, microcephaly, delayed mental development, and hematopoietic dysfunction and has recently been proposed as a disease paradigm. Acute and severe presentations include aplastic anemia, myelodysplastic syndrome, or leukemia, requiring bone marrow transplantation during childhood. Conversely, non-hematological manifestations may exhibit a prolonged and nonspecific clinical trajectory, with growth failure and developmental delay, most of which are often overlooked, particularly in patients with milder symptoms. Here, we describe the clinical course of a girl with a wide spectrum of clinical presentations, including nonspecific hematopoietic disorders, growth retardation, mild developmental delay, amblyopia, hemophagocytic lymphohistiocytosis, and verruca vulgaris, culminating in a genetic diagnosis of AMeD syndrome at 12 years of age. We also summarized the clinical manifestations of previously reported cases of AMeD syndrome. Cumulatively, 13 females and 5 males have been documented, with a cardinal triad of symptoms, aplastic anemia, short stature, and intellectual disability. Additional characteristic observations included pigmentary deposition in approximately half of the cases and skeletal difficulties in one-quarter. We propose that early diagnosis of patients who exhibit relatively mild phenotypes of skin or skeletal lesions is important for managing and improving the quality of life of patients with AMeD syndrome.

Implementation of and Systems-Level Barriers to Guideline-Driven Germline Genetic Evaluation in the Care of Patients With Myelodysplastic Syndrome and Acute Myeloid Leukemia

PURPOSE

Knowledge of an inherited predisposition to myelodysplastic syndrome (MDS) and AML has important clinical implications for treatment decisions, surveillance, and care of at-risk relatives. National Comprehensive Cancer Network (NCCN) guidelines recently incorporated recommendations for germline genetic evaluation of patients with MDS/AML on the basis of personal and family history features, but the practicality of implementing these recommendations has not been studied.

METHODS

A hereditary hematology quality improvement (QI) committee was formed to implement these guidelines in a prospective cohort of patients diagnosed with MDS/AML. Referral for germline genetic testing was recommended for patients meeting NCCN guideline criteria. Referral patterns and genetic evaluation outcomes were compared with a historical cohort of patients with MDS/AML. Barriers to evaluation were identified.

RESULTS

Of the 90 patients with MDS/AML evaluated by the QI committee, 59 (66%) met criteria for germline evaluation. Implementation of the QI committee led to more referrals for germline evaluation in accordance with NCCN guidelines (31% v 14%, P = .03). However, the majority of those meeting criteria were never referred due to high medical acuity or being deceased or in hospice at the time of QI committee recommendations. Despite this, two (17%) of the 12 patients undergoing genetic testing were diagnosed with a hereditary myeloid malignancy syndrome.

CONCLUSION

Current NCCN guidelines resulted in two thirds of patients with MDS/AML meeting criteria for germline evaluation. A hereditary hematology-focused QI committee aided initial implementation and modestly improved NCCN guideline adherence. However, the high morbidity and mortality and prolonged inpatient stays associated with MDS/AML challenged traditional outpatient genetic counseling models. Further improvements in guideline adherence require innovating new models of genetic counseling and testing for this patient population.

Cancer risks related to intellectual disabilities: A systematic review

BACKGROUND

People with intellectual disabilities (ID) face barriers in cancer care contributing to poorer oncological outcomes. Yet, understanding cancer risks in the ID population remains incomplete.

AIM

To provide an overview of cancer incidence and cancer risk assessments in the entire ID population as well as within ID-related disorders.

METHODS

This systematic review examined cancer risk in the entire ID population and ID-related disorders. We systematically searched PubMed (MEDLINE) and EMBASE for literature from January 1, 2000 to July 15, 2022 using a search strategy combining terms related to cancer, incidence, and ID.

RESULTS

We found 55 articles assessing cancer risks in the ID population at large groups or in subgroups with ID-related syndromes, indicating that overall cancer risk in the ID population is lower or comparable with that of the general population, while specific disorders (e.g., Down's syndrome) and certain genetic mutations may elevate the risk for particular cancers.

DISCUSSION

The heterogeneity within the ID population challenges precise cancer risk assessment at the population level. Nonetheless, within certain subgroups, such as individuals with specific ID-related disorders or certain genetic mutations, a more distinct pattern of varying cancer risks compared to the general population becomes apparent.

CONCLUSION

More awareness, and personalized approach in cancer screening within the ID population is necessary.

First report of familial mixed phenotype acute leukemia: shared clinical characteristics, Philadelphia translocation, and germline variants

While our understanding of the molecular basis of mixed phenotype acute leukemia (MPAL) has progressed over the decades, our knowledge is limited and the prognosis remains poor. Investigating cases of familial leukemia can provide insights into the role of genetic and environmental factors in leukemogenesis. Although familial cases and associated mutations have been identified in some leukemias, familial occurrence of MPAL has never been reported. Here, we report the first cases of MPAL in a family. A 68-year-old woman was diagnosed with MPAL and received haploidentical stem cell transplantation from her 44-year-old son. In four years, the son himself developed MPAL. Both cases exhibited similar characteristics such as biphenotypic leukemia with B/myeloid cell antigens, Philadelphia translocation (BCR-ABL1 mutation), and response to acute lymphoblastic leukemia-type chemotherapy. These similarities suggest the presence of hereditary factors contributing to the development of MPAL. Targeted sequencing identified shared germline variants in these cases; however, in silico analyses did not strongly support their pathogenicity. Intriguingly, when the son developed MPAL, the mother did not develop donor-derived leukemia and remained in remission. Our cases provide valuable insights to guide future research on familial MPAL.

Alternative DNA structures in hematopoiesis and adaptive immunity

Besides the canonical B-form, DNA also adopts alternative non-B form conformations which are highly conserved in all domains of life. While extensive research over decades has centered on the genomic functions of B-form DNA, understanding how non-B-form conformations influence functional genomic states remains a fundamental and open question. Recent studies have ascribed alternative DNA conformations such as G-quadruplexes and R-loops as important functional features in eukaryotic genomes. This review delves into the biological importance of alternative DNA structures, with a specific focus on hematopoiesis and adaptive immunity. We discuss the emerging roles of G-quadruplex and R-loop structures, the two most well-studied alternative DNA conformations, in the hematopoietic compartment and present evidence for their functional roles in normal cellular physiology and associated pathologies.

Treatment of Fanconi anemia patient with synchronous esophageal and tongue cancer in COVID-19 era: a case report

Although Fanconi anemia patients accompany a high risk of multiple cancers, radiation therapy on these patients has been carried out only in limited cases due to the concern for radiation toxicity that stems from their susceptibility to radiation. We report a case of a 28-year-old female patient diagnosed as synchronous esophageal and tongue cancer, and underwent two cycles of radiation therapy, inevitably in the condition of coronavirus disease 2019 infection. She received radiation therapy of 30 Gy to esophageal mass with neoadjuvant aim in her first-round radiation therapy, and later received 27 Gy to tongue cancer surgical bed with adjuvant aim in her second-round radiation therapy. With no further treatment, she has been maintaining no evidence of disease state for 7 months. Managing Fanconi anemia patients with multiple cancers using radiation therapy is feasible, in which cases a dose de-escalation may be important considering the radiation toxicity and possible future re-treatment.

Profiling salivary miRNA expression levels in Fanconi anemia patients - a pilot study

The overarching goal of this study is to predict the risk of developing oral squamous cell carcinoma (OSCC) in Fanconi anemia (FA) patients. We have compared the microRNA (miRNA, miR) expression levels in saliva samples from FA patients (n = 50) who are at a low-moderate and/or high risk of developing OSCC to saliva samples from healthy controls (n = 16). The miRNA expression levels in saliva samples were quantified using qPCR. We observed that miR-744, miR-150-5P, and miR-146B-5P had the best discriminatory capacity between FA patients and controls, with an area under the curve (AUC) of 94.0%, 92.9% and 85.3%, respectively. Our data suggest that miR-1, miR-146B-5P, miR-150-5P, miR-155-5P, and miR-744 could be used as panel to predict the risk of developing OSCC in FA patients, with a 89.3% sensitivity and a 68.2% specificity (AUC = 81.5%). Our preliminary data support the notion that the expression levels of salivary miRNAs have the potential to predict the risk of developing OSCC in FA patients and in the future may reduce deaths associated with OSCC.

Exploring the hub genes and potential drugs involved in Fanconi anemia using microarray datasets and bioinformatics analysis

Fanconi anemia (FA) is a genetic disorder that occurs when certain genes responsible for repairing DNA replication and promoting homologous recombination fail to function properly. This leads to severe clinical symptoms and a wide range of cancer-related characteristics. Recent treatment approaches for FA involve hematopoietic stem cell transplantation (HSCT), which helps restore the population of stem cells. A survival study using p-values indicated that specific hub genes play a significant role in diagnosing and predicting the disease. To find potential medications that interact with the identified hub genes, researchers inferred drugs. Among hub genes, TP53 was found to be particularly promising through computational analysis. Further investigation focused on two drugs, Topiramate and Tocofersolan predicted based on drug bank database analysis. Molecular docking strategies were employed to assess the best binding pose of these drugs with TP53. Topiramate showed a binding affinity of -6.5 kcal/mol, while Tocofersolan showed -8.5 kcal/mol against the active residues within the binding pocket. Molecular dynamics (MD) simulations were conducted to observe the stability of each drug's interaction with the TP53 protein over time. Both drugs exhibited stable confirmation with only slight changes in the loop region of the TP53 protein during the simulation intervals. Results also shows that there was a high fluctuation observed during apo-sate simulation time intervals as compared to complex system. Hence, it is suggested that the exploration of structure-based drug design holds promising results to specific target. This could potentially lead to a breakthrough in future experimental approaches for FA treatment.Communicated by Ramaswamy H. Sarma.

Management of Fanconi anemia beyond childhood

Fanconi anemia (FA) has long been considered a severe inherited bone marrow failure (BMF) disorder of early childhood. Thus, management of this multisystem disorder has previously been unfamiliar to many hematologists specializing in the care of adolescents and young adults (AYA). The increased diagnosis of FA in AYA patients, facilitated by widely available germline genomic testing, improved long-term survival of children with FA following matched sibling and alternative donor hematopoietic stem cell transplantation (HSCT) performed for BMF, and expanding need in the near future for long-term monitoring in patients achieving hematologic stabilization following ex vivo gene therapy are all reasons why management of FA in AYA populations deserves specific consideration. In this review, we address the unique challenges and evidence-based practice recommendations for the management of AYA patients with FA. Specific topics addressed include hematologic monitoring in AYA patients yet to undergo HSCT, management of myeloid malignancies occurring in FA, diagnosis and management of nonhematologic malignances and organ dysfunction in AYA patients with FA, and evolving considerations for the long-term monitoring of patients with FA undergoing gene therapy.

Germline Predisposition to Myeloid Neoplasms: Diagnostic Concepts and Classifications

Molecular and sequencing advances have led to substantial breakthroughs in the discovery of new genes and inherited mutations associated with increased risk of developing myeloid malignancies. Many of the same germline mutated genes are also drivers of malignancy in sporadic cancer. Recognition of myeloid malignancy associated with germline mutations is essential for proper therapy, disease surveillance, informing related donor selection for hematopoietic stem cell transplantation, and genetic counseling of the patient and affected family members. Some germline mutations are associated with syndromic features that precede the development of malignancy; however, penetrance may be highly variable leading to masking of the syndromic phenotype and/or inherited etiology.

Androgen use in bone marrow failures and myeloid neoplasms: Mechanisms of action and a systematic review of clinical data

Despite recent advancements, treatment of cytopenia due to bone marrow failures (BMF) and myeloid neoplasms remains challenging. Androgens promote renewal and maturation of blood cells and may be beneficial in these forms. Here we report a systematic review of androgens use as single agent in hematologic conditions. Forty-six studies, mainly retrospective with various androgen types and doses, were included: 12 on acquired aplastic anemia (AA), 11 on inherited BMF, 17 on myelodysplastic syndromes (MDS), and 7 on myelofibrosis. Responses ranged from 50 to 70% in inherited BMF, 40-50% in acquired AA and MDS, while very limited evidence emerged for myelofibrosis. In acquired AA, response was associated with presence of non-severe disease; in MDS androgens were more effective on thrombocytopenia or mild to moderate anemia, whilst limited benefit was observed for transfusion dependent anemia. Toxicity profile mainly consisted of virilization and liver enzyme elevation, whilst the risk of leukemic evolution remains controversial.

Comprehensive laboratory diagnosis of Fanconi anaemia: comparison of cellular and molecular analysis

BACKGROUND

Fanconi anaemia (FA) is a rare inherited bone marrow failure disease caused by germline pathogenic variants in any of the 22 genes involved in the FA-DNA interstrand crosslink (ICL) repair pathway. Accurate laboratory investigations are required for FA diagnosis for the clinical management of the patients. We performed chromosome breakage analysis (CBA), FANCD2 ubiquitination (FANCD2-Ub) analysis and exome sequencing of 142 Indian patients with FA and evaluated the efficiencies of these methods in FA diagnosis.

METHODS

We performed CBA and FANCD2-Ub analysis in the blood cells and fibroblasts of patients with FA. Exome sequencing with improved bioinformatics to detect the single number variants and CNV was carried out for all the patients. Functional validation of the variants with unknown significance was done by lentiviral complementation assay.

RESULTS

Our study showed that FANCD2-Ub analysis and CBA on peripheral blood cells could diagnose 97% and 91.5% of FA cases, respectively. Exome sequencing identified the FA genotypes consisting of 45 novel variants in 95.7% of the patients with FA. FANCA (60.2%), FANCL (19.8%) and FANCG (11.7%) were the most frequently mutated genes in the Indian population. A FANCL founder mutation c.1092G>A; p.K364=was identified at a very high frequency (~19%) in our patients.

CONCLUSION

We performed a comprehensive analysis of the cellular and molecular tests for the accurate diagnosis of FA. A new algorithm for rapid and cost-effective molecular diagnosis for~90% of FA cases has been established.

Mutations of BRCA1, BRCA2, and PALB2 Genes in Breast Tumor Tissue: Relationship with the Effectiveness of Neoadjuvant Chemotherapy and Disease Prognosis

It has been shown that the loss of function of the BRCA1, BRCA2, and PALB2 genes due to a number of hereditary mutations or chromosomal aberrations can affect the effectiveness of chemotherapy treatment and disease prognosis in patients with various types of cancer, and in particular in breast cancer. Thus, the aim of the work was to evaluate the predictive and prognostic potential of DNA copy number aberrations and mutations in the BRCA1, BRCA2, and PALB2 genes in breast tumors.

MATERIALS AND METHODS

The study included 66 patients with breast cancer. DNA copy number aberrations (CNA) were assessed by high-density CytoScanHD™ Array micro matrix analysis. Gene mutations were assessed by sequencing on the MiSeq™ Sequencing System using the Accel-Amplicon BRCA1, BRCA2, and PALB2 Panel.

RESULTS

It has been established that the presence of a normal copy number of PALB2 is associated with a lack of response to chemotherapy in Taxotere-containing treatment regimens (p = 0.05). In addition, the presence of a PALB2 deletion is associated with 100% metastatic survival rates (log-rank test p = 0.04). As a result of sequencing, 25 mutations were found in the BRCA1 gene, 42 mutations in BRCA2, and 27 mutations in the PALB2 gene. The effect of mutations on the effectiveness of treatment is controversial, but an effect on the survival of patients with breast cancer has been shown. So, in the presence of pathogenic mutations in the BRCA2 gene, 100% metastatic survival is observed (log-rank test p = 0.05), as well as in the elimination of PALB2 mutations during treatment (log-rank test p = 0.07).

CONCLUSION

Currently, there is little data on the effect of chromosomal aberrations and mutations in the BRCA1/2 and PALB2 genes on the effectiveness of treatment and prognosis of the disease. At the same time, the study of these genes has great potential for testing focused on a personalized approach to the treatment of patients with breast cancer.

Graft-versus-host disease and other cutaneous manifestations in pediatric patients transplanted for Fanconi anemia

OBJECTIVE

The aim of this study was to elaborate a specific protocol for the assessment and early identification of skin lesions in pediatric patients with Fanconi anemia undergoing hematopoietic stem cell transplantation.

METHODS

This is a longitudinal, retrospective, and descriptive study. The medical records of 136 pediatric patients with Fanconi anemia who underwent hematopoietic stem cell transplantation between 2008 and 2018 at the Clinical Hospital of the Federal University of Paraná were reviewed. A specific protocol was created for data collection, which included age, sex, skin color, age at diagnosis of Fanconi anemia, transplantation data, family history of consanguinity, and pre- and post-transplant complications. In addition, the data included the presence of graft-versus-host disease of the skin and other organs, its classification, type of lesion, location, and also skin lesions not related to graft-versus-host disease.

RESULTS

Among the skin manifestations in pre-transplant period, café-au-lait spots stood out (32.4%). At least one organ was affected by graft-versus-host disease in 55.1% of patients; the most common involvement being the mouth, followed by the skin. Rash and erythema were the most frequently observed cutaneous manifestations of graft-versus-host disease.

CONCLUSION

A high prevalence of cutaneous manifestations of the disease was observed, as well as cutaneous manifestations of graft-versus-host disease. The protocol developed gathers relevant and standardized information for the follow-up of patients with Fanconi anemia undergoing hematopoietic stem cell transplantation, ensuring greater reliability of the information, and its implementation will allow the prospective evaluation of patients.

Circular RNAs drive oncogenic chromosomal translocations within the MLL recombinome in leukemia

The first step of oncogenesis is the acquisition of a repertoire of genetic mutations to initiate and sustain the malignancy. An important example of this initiation phase in acute leukemias is the formation of a potent oncogene by chromosomal translocations between the mixed lineage leukemia (MLL) gene and one of 100 translocation partners, known as the MLL recombinome. Here, we show that circular RNAs (circRNAs)-a family of covalently closed, alternatively spliced RNA molecules-are enriched within the MLL recombinome and can bind DNA, forming circRNA:DNA hybrids (circR loops) at their cognate loci. These circR loops promote transcriptional pausing, proteasome inhibition, chromatin re-organization, and DNA breakage. Importantly, overexpressing circRNAs in mouse leukemia xenograft models results in co-localization of genomic loci, de novo generation of clinically relevant chromosomal translocations mimicking the MLL recombinome, and hastening of disease onset. Our findings provide fundamental insight into the acquisition of chromosomal translocations by endogenous RNA carcinogens in leukemia.

Fludarabine-Based Low-Intensity Conditioning for Fanconi Anemia is Associated with Good Outcomes in Aplastic Anemia but not in MDS - a Single-Center Experience

Background

Hematopoietic stem cell transplantation (HSCT) is the only curative option for patients with Fanconi Anemia (FA) with hematological abnormalities.

Materials and Methods

This is a retrospective analysis of patients with FA who underwent a matched-related donor HSCT.

Results

Sixty patients underwent 65 transplants between 1999-2021 using a fludarabine-based low-intensity conditioning regimen. The median age at transplant was 11 years (range: 3-37). Aplastic anemia (AA) was the underlying diagnosis in 55 (84.6%), while 8 (12.4%) had myelodysplastic syndrome (MDS) and 2 (3%) had acute myeloid leukemia (AML). The conditioning regimen used was Fludarabine with low-dose Cyclophosphamide for aplastic anemia and Fludarabine with low-dose Busulfan for MDS/AML. Graft versus host disease (GVHD) prophylaxis consisted of Cyclosporine and methotrexate. Peripheral blood was the predominant stem cell graft source (86.2%). Engraftment occurred in all but one patient. The median time to neutrophil and platelet engraftment was 13 days (range: 9-29) & 13 days (range: 5-31), respectively. Day 28 chimerism analysis showed complete chimerism in 75.4 % and mixed chimerism in 18.5%. Secondary graft failure was encountered in 7.7%. Grade II-IV acute GVHD occurred in 29.2%, while Grade III-IV acute GVHD occurred in 9.2%. Chronic GVHD was seen in 58.5% and was limited in most patients. The median follow-up is 55 months (range: 2-144) & the 5-year estimated overall survival (OS) is 80.2 ± 5.1%. Secondary malignancies were noted in 4 patients. The 5-year OS was significantly higher in patients undergoing HSCT for AA (86.6 + 4.7%) as compared to MDS/AML (45.7+16.6%) (p= 0.001).

Conclusion

SCT using a fully matched donor provides good outcomes with low-intensity conditioning regimens in patients with FA who have aplastic marrow.

Telomere biology: from disorders to hematological diseases

Variations in the length of telomeres and pathogenic variants involved in telomere length maintenance have been correlated with several human diseases. Recent breakthroughs in telomere biology knowledge have contributed to the identification of illnesses named "telomeropathies" and revealed an association between telomere length and disease outcome. This review emphasizes the biology and physiology aspects of telomeres and describes prototype diseases in which telomeres are implicated in their pathophysiology. We also provide information on the role of telomeres in hematological diseases ranging from bone marrow failure syndromes to acute and chronic leukemias.

Fanconi anemia-associated chromosomal radial formation is dependent on POLθ-mediated alternative end joining

Activation of the Fanconi anemia (FA) pathway after treatment with mitomycin C (MMC) is essential for preventing chromosome translocations termed "radials." When replication forks stall at MMC-induced interstrand crosslinks (ICLs), the FA pathway is activated to orchestrate ICL unhooking and repair of the DNA break intermediates. However, in FA-deficient cells, how ICL-associated breaks are resolved in a manner that leads to radials is unclear. Here, we demonstrate that MMC-induced radials are dependent on DNA polymerase theta (POLθ)-mediated alternative end joining (A-EJ). Specifically, we show that radials observed in FANCD2^-/- cells are dependent on POLθ and DNA ligase III and occur independently of classical non-homologous end joining. Furthermore, treatment of FANCD2^-/- cells with POLθ inhibitors abolishes radials and leads to the accumulation of breaks co-localizing with common fragile sites. Uniformly, these observations implicate A-EJ in radial formation and provide mechanistic insights into the treatment of FA pathway-deficient cancers with POLθ inhibitors.

Proteomic Characterization of Acute Myeloid Leukemia for Precision Medicine

Acute myeloid leukemia (AML) is a highly heterogeneous cancer of the hematopoietic system with no cure for most patients. In addition to chemotherapy, treatment options for AML include recently approved therapies that target proteins with roles in AML pathobiology, such as FLT3, BLC2, and IDH1/2. However, due to disease complexity, these therapies produce very diverse responses, and survival rates are still low. Thus, despite considerable advances, there remains a need for therapies that target different aspects of leukemic biology and for associated biomarkers that define patient populations likely to respond to each available therapy. To meet this need, drugs that target different AML vulnerabilities are currently in advanced stages of clinical development. Here, we review proteomics and phosphoproteomics studies that aimed to provide insights into AML biology and clinical disease heterogeneity not attainable with genomic approaches. To place the discussion in context, we first provide an overview of genetic and clinical aspects of the disease, followed by a summary of proteins targeted by compounds that have been approved or are under clinical trials for AML treatment and, if available, the biomarkers that predict responses. We then discuss proteomics and phosphoproteomics studies that provided insights into AML pathogenesis, from which potential biomarkers and drug targets were identified, and studies that aimed to rationalize the use of synergistic drug combinations. When considered as a whole, the evidence summarized here suggests that proteomics and phosphoproteomics approaches can play a crucial role in the development and implementation of precision medicine for AML patients.

Ph-Positive B-Cell Acute Lymphoblastic Leukemia Occurring after Receipt of Bivalent SARS-CoV-2 mRNA Vaccine Booster: A Case Report

The coronavirus disease 2019 (COVID-19) pandemic is a universal emergency public health issue. A large proportion of the world's population has had several spike antigen exposures to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections and/or COVID-19 vaccinations in a relatively short-term period. Although sporadic hematopoietic adverse events after COVID-19 vaccine inoculation were reported, there is currently no sufficient evidence correlating anti-spike protein immune responses and hematopoietic adverse events of vaccinations. We reported the first case of Ph-positive B-cell acute lymphoblastic leukemia (ALL) occurring after a bivalent mRNA COVID-19 vaccine inoculation. The otherwise healthy 43-year-old female patient had a total of six spike antigen exposures in the past 1.5 years. Informative pre-vaccine tests and bone marrow study results were provided. Although the causal relationship between bivalent vaccinations and the subsequent development of Ph-positive B-cell ALL cannot be determined in the case report, we propose that anti-spike protein immune responses could be a trigger for leukemia. Clinicians must investigate the hematopoietic adverse events closely after COVID-19 vaccinations. Further pre-clinical studies to investigate the safety of bivalent mRNA COVID-19 vaccine are required.

Inherited bone marrow failure syndromes: a review of current practices and potential future research directions

PURPOSE OF REVIEW

Recent advances in diagnosis and treatment of inherited bone marrow failure syndromes (IBMFS) have significantly improved disease understanding and patient outcomes. Still, IBMFS present clinical challenges that require further progress. This review aims to provide an overview of the current state of diagnosis and treatment modalities of the major IBMFS seen in paediatrics and present areas of prioritization for future research.

RECENT FINDINGS

Haematopoietic cell transplantation (HCT) for IBMFS has greatly improved in recent years, shifting the research and clinical focus towards cancer predispositions and adverse effects of treatment. Each year, additional novel genes and pathogenic variants are described, and genotype-phenotype mapping becomes more sophisticated. Moreover, novel therapeutics exploring disease-specific mechanisms show promise to complement HCT and treat patients who cannot undergo current treatment options.

SUMMARY

Research on IBMFS should have short-term and long-term goals. Immediate challenges include solidifying diagnostic and treatment guidelines, cancer detection and treatment, and continued optimization of HCT. Long-term goals should emphasize genotype-phenotype mapping, genetic screening tools and gene-targeted therapy.

The International Consensus Classification (ICC) of hematologic neoplasms with germline predisposition, pediatric myelodysplastic syndrome, and juvenile myelomonocytic leukemia

Updating the classification of hematologic neoplasia with germline predisposition, pediatric myelodysplastic syndrome (MDS), and juvenile myelomonocytic leukemia (JMML) is critical for diagnosis, therapy, research, and clinical trials. Advances in next-generation sequencing technology have led to the identification of an expanding group of genes that predispose to the development of hematolymphoid neoplasia when mutated in germline configuration and inherited. This review encompasses recent advances in the classification of myeloid and lymphoblastic neoplasia with germline predisposition summarizing important genetic and phenotypic information, relevant laboratory testing, and pathologic bone marrow features. Genes are organized into three major categories including (1) those that are not associated with constitutional disorder and include CEBPA, DDX41, and TP53; (2) those associated with thrombocytopenia or platelet dysfunction including RUNX1, ANKRD26, and ETV6; and (3) those associated with constitutional disorders affecting multiple organ systems including GATA2, SAMD9, and SAMD9L, inherited genetic mutations associated with classic bone marrow failure syndromes and JMML, and Down syndrome. A provisional category of germline predisposition genes is created to recognize genes with growing evidence that may be formally included in future revised classifications as substantial supporting data emerges. We also detail advances in the classification of pediatric myelodysplastic syndrome (MDS), expanding the definition of refractory cytopenia of childhood (RCC) to include early manifestation of MDS in patients with germline predisposition. Finally, updates in the classification of juvenile myelomonocytic leukemia are presented which genetically define JMML as a myeloproliferative/myelodysplastic disease harboring canonical RAS pathway mutations. Diseases with features overlapping with JMML that do not carry RAS pathway mutations are classified as JMML-like. The review is based on the International Consensus Classification (ICC) of Myeloid and Lymphoid Neoplasms as reported by Arber et al. (Blood 140(11):1200-1228, 2022).

Germline Pathogenic Variants in Squamous Cell Carcinoma of the Head and Neck

Head and neck squamous cell carcinoma (HNSCC) presents a significant global health problem with variable geographic distribution and risk factors, including tobacco and alcohol abuse, human papillomavirus infections, and genetic predisposition. While the majority of cases are sporadic, several well-defined hereditary syndromes have been associated with a higher risk of developing HNSCC including Li-Fraumeni syndrome, Fanconi anaemia, Bloom syndrome, familial atypical multiple mole melanoma, and dyskeratosis congenita. There is also evidence of familial clusters of HNSCC, suggesting a genetic component in the development of the disease. Germ-line genetic testing in HNSCC using next-generation sequencing has revealed a wide range of germline variants, some of which were not anticipated based on standard guidelines. These variants may influence treatment decisions and have the potential to be targeted with precision medicine in the future. Despite these advances, routine germline genetic testing for HNSCC is not currently recommended and remains reserved for HNSCC cases with early onset or strong family cancer history. However, the increasing availability of germline genetic testing warrants development of more comprehensive and standardized testing protocols. Germline genetic testing also has the potential to influence precision-guided treatment in HNSCC patients carrying germline pathogenic variants.

Modern management of Fanconi anemia

In this review, we present a clinical case report and discussion to outline the importance of long-term specific Fanconi anemia (FA) monitoring, and we discuss the main aspects of the general management of patients with FA and clinical complications. While several nontransplant treatments are currently under evaluation, hematopoietic stem cell transplantation (HSCT) remains the only therapeutic option for bone marrow failure (BMF). Although HSCT outcomes in patients with FA have remarkably improved over the past 20 years, in addition to the mortality intrinsic to the procedure, HSCT increases the risk and accelerates the appearance of late malignancies. HSCT offers the best outcome when performed in optimal conditions (moderate cytopenia shifting to severe, prior to transfusion dependence and before clonal evolution or myelodysplasia/acute myeloid leukemia); hence, an accurate surveillance program is vital. Haploidentical HSCT offers very good outcomes, although long-term effects on malignancies have not been fully explored. A monitoring plan is also important to identify cancers, particularly head and neck carcinomas, in very early phases. Gene therapy is still experimental and offers the most encouraging results when performed in early phases of BMF by infusing high numbers of corrected cells without genotoxic effects. Patients with FA need comprehensive monitoring and care plans, coordinated by centers with expertise in FA management, that start at diagnosis and continue throughout life. Such long-term follow-up is essential to detect complications related to the disease or treatment in this setting.

Role of Germline Predisposition to Therapy-Related Myeloid Neoplasms

PURPOSE OF REVIEW

Therapy-related myeloid neoplasms (t-MNs) are aggressive leukemias that develop following exposure to DNA-damaging agents. A subset of patients developing t-MN may have an inherited susceptibility to develop myeloid neoplasia. Herein, we review studies reporting t-MN and their association with a germline or inherited predisposition.

RECENT FINDINGS

Emerging evidence suggests that development of t-MN is the result of complex interactions including generation of somatic variants in hematopoietic stem cells and/or clonal selection pressure exerted by the DNA-damaging agents, and immune evasion on top of any inherited genetic susceptibility. Conventionally, alkylating agents, topoisomerase inhibitors, and radiation have been associated with t-MN. Recently, newer modalities including poly (ADP-ribose) polymerase inhibitors (PARPi) and peptide receptor radionucleotide therapy (PRRT) are associated with t-MN. At the same time, the role of pathogenic germline variants (PGVs) in genes such as BRCA1/2, BARD1, or TP53 on the risk of t-MN is being explored. Moreover, studies have shown that while cytotoxic therapy increases the risk of developing myeloid neoplasia, it may be exposing the vulnerability of an underlying germline predisposition. t-MN remains a disease with poor prognosis. Studies are needed to better define an individual's inherited neoplastic susceptibility which will help predict the risk of myeloid neoplasia in the future. Understanding the genes driving the inherited neoplastic susceptibility will lead to better patient- and cancer-specific management including choice of therapeutic regimen to prevent, or at least delay, development of myeloid neoplasia after treatment of a prior malignancy.

Cytogenetics in Fanconi Anemia: The Importance of Follow-Up and the Search for New Biomarkers of Genomic Instability

Fanconi Anemia (FA) is a disease characterized by genomic instability, increased sensitivity to DNA cross-linking agents, and the presence of clonal chromosomal abnormalities. This genomic instability can compromise the bone marrow (BM) and confer a high cancer risk to the patients, particularly in the development of Myelodysplastic Syndrome (MDS) and Acute Myeloid Leukemia (AML). The diagnosis of FA patients is complex and cannot be based only on clinical features at presentation. The gold standard diagnostic assay for these patients is cytogenetic analysis, revealing chromosomal breaks induced by DNA cross-linking agents. Clonal chromosome abnormalities, such as the ones involving chromosomes 1q, 3q, and 7, are also common features in FA patients and are associated with progressive BM failure and/or a pre-leukemia condition. In this review, we discuss the cytogenetic methods and their application in diagnosis, stratification of the patients into distinct prognostic groups, and the clinical follow-up of FA patients. These methods have been invaluable for the understanding of FA pathogenesis and identifying novel disease biomarkers. Additional evidence is required to determine the association of these biomarkers with prognosis and cancer risk, and their potential as druggable targets for FA therapy.

Polyclonal evolution of Fanconi anemia to MDS and AML revealed at single cell resolution

Background

Fanconi anemia (FA) is a rare disease of bone marrow failure. FA patients are prone to develop myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). However, the molecular clonal evolution of the progression from FA to MDS/AML remains elusive.

Methods

Herein, we performed a comprehensive genomic analysis using an FA patient (P1001) sample that transformed to MDS and subsequently AML, together with other three FA patient samples at the MDS stage.

Results

Our finding showed the existence of polyclonal pattern in these cases at MDS stage. The clonal evolution analysis of FA case (P1001) showed the mutations of UBASH3A, SF3B1, RUNX1 and ASXL1 gradually appeared at the later stage of MDS, while the IDH2 alteration become the dominant clone at the leukemia stage. Moreover, single-cell sequencing analyses further demonstrated a polyclonal pattern was present at either MDS or AML stages, whereas IDH2 mutated cell clones appeared only at the leukemia stage.

Conclusions

We thus propose a clonal evolution model from FA to MDS and AML for this patient. The results of our study on the clonal evolution and mutated genes of the progression of FA to AML are conducive to understanding the progression of the disease that still perplexes us.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40164-022-00319-5.

Fanconi anemia and dyskeratosis congenita/telomere biology disorders: Two inherited bone marrow failure syndromes with genomic instability

Inherited bone marrow failure syndromes (IBMFS) are a complex and heterogeneous group of genetic diseases. To date, at least 13 IBMFS have been characterized. Their pathophysiology is associated with germline pathogenic variants in genes that affect hematopoiesis. A couple of these diseases also have genomic instability, Fanconi anemia due to DNA damage repair deficiency and dyskeratosis congenita/telomere biology disorders as a result of an alteration in telomere maintenance. Patients can have extramedullary manifestations, including cancer and functional or structural physical abnormalities. Furthermore, the phenotypic spectrum varies from cryptic features to patients with significantly evident manifestations. These diseases require a high index of suspicion and should be considered in any patient with abnormal hematopoiesis, even if extramedullary manifestations are not evident. This review describes the disrupted cellular processes that lead to the affected maintenance of the genome structure, contrasting the dysmorphological and oncological phenotypes of Fanconi anemia and dyskeratosis congenita/telomere biology disorders. Through a dysmorphological analysis, we describe the phenotypic features that allow to make the differential diagnosis and the early identification of patients, even before the onset of hematological or oncological manifestations. From the oncological perspective, we analyzed the spectrum and risks of cancers in patients and carriers.

Genetic Disorders with Predisposition to Paediatric Haematopoietic Malignancies—A Review

The view of paediatric cancer as a genetic disease arises as genetic research develops. Germline mutations in cancer predisposition genes have been identified in about 10% of children. Paediatric cancers are characterized by heterogeneity in the types of genetic alterations that drive tumourigenesis. Interactions between germline and somatic mutations are a key determinant of cancer development. In 40% of patients, the family history does not predict the presence of inherited cancer predisposition syndromes and many cases go undetected. Paediatricians should be aware of specific symptoms, which highlight the need of evaluation for cancer syndromes. The quickest possible identification of such syndromes is of key importance, due to the possibility of early detection of neoplasms, followed by presymptomatic genetic testing of relatives, implementation of appropriate clinical procedures (e.g., avoiding radiotherapy), prophylactic surgical resection of organs at risk, or searching for donors of hematopoietic stem cells. Targetable driver mutations and corresponding signalling pathways provide a novel precision medicine strategy.Therefore, there is a need for multi-disciplinary cooperation between a paediatrician, an oncologist, a geneticist, and a psychologist during the surveillance of families with an increased cancer risk. This review aimed to emphasize the role of cancer-predisposition gene diagnostics in the genetic surveillance and medical care in paediatric oncology.

The incidence and spectrum of congenital hand differences in patients with Fanconi anaemia: analysis of 48 patients

We analysed the spectrum of congenital hand differences in a cohort of patients with Fanconi anaemia (FA). Data of 48 FA patients at the National Cancer Institute were reviewed focusing on age at diagnosis, type and severity of limb difference and any potential association with other known clinical anomalies that are part of the FA phenotype, specifically VACTERL-H and PHENOS. Twenty-eight patients had an upper limb difference, which always included thumb hypoplasia. Twenty-three patients had bilateral upper limb differences, including varying combinations and severities of thumb hypoplasia, radial dysplasia and thumb duplication. Patients with a limb difference were diagnosed at a younger age (<2 years: 15/28 with limb anomaly versus 4/20 without a limb anomaly). However, 7/28 with limb anomalies, usually thumb hypoplasia, were not diagnosed until after 6 years of age. This study demonstrates the broad spectrum of radial ray anomalies within the FA phenotype along with the possibility of either unilateral or bilateral upper limb differences and adds further merit to consideration of screening for FA in all cases of radial ray anomaly.Level of evidence: II.

FANCD2 maintains replication fork stability during misincorporation of the DNA demethylation products 5-hydroxymethyl-2'-deoxycytidine and 5-hydroxymethyl-2'-deoxyuridine

Fanconi anemia (FA) is a rare hereditary disorder caused by mutations in any one of the FANC genes. FA cells are mainly characterized by extreme hypersensitivity to interstrand crosslink (ICL) agents. Additionally, the FA proteins play a crucial role in concert with homologous recombination (HR) factors to protect stalled replication forks. Here, we report that the 5-methyl-2'-deoxycytidine (5mdC) demethylation (pathway) intermediate 5-hydroxymethyl-2'-deoxycytidine (5hmdC) and its deamination product 5-hydroxymethyl-2'-deoxyuridine (5hmdU) elicit a DNA damage response, chromosome aberrations, replication fork impairment and cell viability loss in the absence of FANCD2. Interestingly, replication fork instability by 5hmdC or 5hmdU was associated to the presence of Poly(ADP-ribose) polymerase 1 (PARP1) on chromatin, being both phenotypes exacerbated by olaparib treatment. Remarkably, Parp1^-/- cells did not show any replication fork defects or sensitivity to 5hmdC or 5hmdU, suggesting that retained PARP1 at base excision repair (BER) intermediates accounts for the observed replication fork defects upon 5hmdC or 5hmdU incorporation in the absence of FANCD2. We therefore conclude that 5hmdC is deaminated in vivo to 5hmdU, whose fixation by PARP1 during BER, hinders replication fork progression and contributes to genomic instability in FA cells.

Fanconi anemia: current insights regarding epidemiology, cancer, and DNA repair

Fanconi anemia is a genetic disorder that is characterized by bone marrow failure, as well as a predisposition to malignancies including leukemia and squamous cell carcinoma (SCC). At least 22 genes are associated with Fanconi anemia, constituting the Fanconi anemia DNA repair pathway. This pathway coordinates multiple processes and proteins to facilitate the repair of DNA adducts including interstrand crosslinks (ICLs) that are generated by environmental carcinogens, chemotherapeutic crosslinkers, and metabolic products of alcohol. ICLs can interfere with DNA transactions, including replication and transcription. If not properly removed and repaired, ICLs cause DNA breaks and lead to genomic instability, a hallmark of cancer. In this review, we will discuss the genetic and phenotypic characteristics of Fanconi anemia, the epidemiology of the disease, and associated cancer risk. The sources of ICLs and the role of ICL-inducing chemotherapeutic agents will also be discussed. Finally, we will review the detailed mechanisms of ICL repair via the Fanconi anemia DNA repair pathway, highlighting critical regulatory processes. Together, the information in this review will underscore important contributions to Fanconi anemia research in the past two decades.

Head and Neck Cancer Susceptibility and Metabolism in Fanconi Anemia

Fanconi anemia (FA) is a rare inherited, generally autosomal recessive syndrome, but it displays X-linked or dominant negative inheritance for certain genes. FA is characterized by a deficiency in DNA damage repair that results in bone marrow failure, and in an increased risk for various epithelial tumors, most commonly squamous cell carcinomas of the head and neck (HNSCC) and of the esophagus, anogenital tract and skin. Individuals with FA exhibit increased human papilloma virus (HPV) prevalence. Furthermore, a subset of anogenital squamous cell carcinomas (SCCs) in FA harbor HPV sequences and FA-deficient laboratory models reveal molecular crosstalk between HPV and FA proteins. However, a definitive role for HPV in HNSCC development in the FA patient population is unproven. Cellular metabolism plays an integral role in tissue homeostasis, and metabolic deregulation is a known hallmark of cancer progression that supports uncontrolled proliferation, tumor development and metastatic dissemination. The metabolic consequences of FA deficiency in keratinocytes and associated impact on the development of SCC in the FA population is poorly understood. Herein, we review the current literature on the metabolic consequences of FA deficiency and potential effects of resulting metabolic reprogramming on FA cancer phenotypes.

Genotype-phenotype and outcome associations in patients with Fanconi anemia: the National Cancer Institute cohort

Fanconi anemia (FA) is caused by pathogenic variants in the FA/BRCA DNA repair pathway genes, and is characterized by congenital abnormalities, bone marrow failure (BMF) and increased cancer risk. We conducted a genotype-phenotype and outcomes study of 203 patients with FA in our cohort. We compared across the genes, FA/BRCA DNA repair pathways (upstream, ID complex and downstream), and type of pathogenic variants (hypomorphic or null). We explored differences between the patients evaluated in our clinic (clinic cohort) and those who provided data remotely (field cohort). Patients with variants in upstream complex pathway had less severe phenotype [lacked VACTERL-H (Vertebral, Anal, Cardiac, Trachea-esophageal fistula, Esophageal/duodenal atresia, Renal, Limb, Hydrocephalus) association and/or PHENOS (Pigmentation, small-Head, small-Eyes, Neurologic, Otologic, Short stature) features]. ID complex was associated with VACTERL-H. The clinic cohort had more PHENOS features than the field cohort. PHENOS was associated with increased risk of BMF, and VACTERL-H with hypothyroidism. The cumulative incidence of severe BMF was 70%, solid tumors (ST) 20% and leukemia 6.5% as the first event. Head and neck and gynecological cancers were the most common ST, with further increased risk after hematopoietic cell transplantation. Among patients with FANCA, variants in exons 27-30 were associated with higher frequency of ST. Overall median survival was 37 years; patients with leukemia or FANCD1/BRCA2 variants had poorest survival. Patients with variants in the upstream complex had better survival than ID or downstream complex (p=0.001 and 0.016, respectively). FA is phenotypically and genotypically heterogeneous; detailed characterization provides new insights towards understanding this complex syndrome and guiding clinical management.

Non-Melanoma Skin Cancers and Other Cutaneous Manifestations in Bone Marrow Failure Syndromes and Rare DNA Repair Disorders

Although most non-melanoma skin cancers are felt to be sporadic in origin, these tumors do play a role in several cancer predisposition syndromes. The manifestations of skin cancers in these hereditary populations can include diagnosis at extremely early ages and/or multiple primary cancers, as well as tumors at less common sites. Awareness of baseline skin cancer risks for these individuals is important, particularly in the setting of treatments that may compromise the immune system and further increase risk of cutaneous malignancies. Additionally, diagnosis of these disorders and management of non-cutaneous manifestations of these diseases have profound implications for both the patient and their family. This review highlights the current literature on the diagnosis, features, and non-melanoma skin cancer risks associated with lesser-known cancer predisposition syndromes, including bone marrow failure disorders, genomic instability disorders, and base excision repair disorders.

BRCA2-DSS1 interaction is dispensable for RAD51 recruitment at replication-induced and meiotic DNA double strand breaks

The interaction between tumor suppressor BRCA2 and DSS1 is essential for RAD51 recruitment and repair of DNA double stand breaks (DSBs) by homologous recombination (HR). We have generated mice with a leucine to proline substitution at position 2431 of BRCA2, which disrupts this interaction. Although a significant number of mutant mice die during embryogenesis, some homozygous and hemizygous mutant mice undergo normal postnatal development. Despite lack of radiation induced RAD51 foci formation and a severe HR defect in somatic cells, mutant mice are fertile and exhibit normal RAD51 recruitment during meiosis. We hypothesize that the presence of homologous chromosomes in close proximity during early prophase I may compensate for the defect in BRCA2-DSS1 interaction. We show the restoration of RAD51 foci in mutant cells when Topoisomerase I inhibitor-induced single strand breaks are converted into DSBs during DNA replication. We also partially rescue the HR defect by tethering the donor DNA to the site of DSBs using streptavidin-fused Cas9. Our findings demonstrate that the BRCA2-DSS1 complex is dispensable for RAD51 loading when the homologous DNA is close to the DSB.

Mishra et al. have generated mice with a single amino acid substitution in BRCA2, which disrupts its interaction with DSS1 resulting in a severe HR defect. They show the interaction to be dispensable for HR at replication induced and meiotic DSBs.

Cancer Predisposition Genes in Adolescents and Young Adults (AYAs): a Review Paper from the Italian AYA Working Group

PURPOSE OF REVIEW

The present narrative systematic review summarizes current knowledge on germline gene mutations predisposing to solid tumors in adolescents and young adults (AYAs).

RECENT FINDINGS

AYAs with cancer represent a particular group of patients with specific challenging characteristics and yet unmet needs. A significant percentage of AYA patients carry pathogenic or likely pathogenic variants (PV/LPVs) in cancer predisposition genes. Nevertheless, knowledge on spectrum, frequency, and clinical implications of germline variants in AYAs with solid tumors is limited. The identification of PV/LPV in AYA is especially critical given the need for appropriate communicative strategies, risk of second primary cancers, need for personalized long-term surveillance, potential reproductive implications, and cascade testing of at-risk family members. Moreover, these gene alterations may potentially provide novel biomarkers and therapeutic targets that are lacking in AYA patients. Among young adults with early-onset phenotypes of malignancies typically presenting at later ages, the increased prevalence of germline PV/LPVs supports a role for genetic counseling and testing irrespective of tumor type.

Allergies, genetic polymorphisms of Th2 interleukins, and childhood acute lymphoblastic leukemia: The ESTELLE study

CONTEXT

A negative association between a history of allergy and childhood acute lymphoblastic leukemia (ALL) has been reported in previous studies, but remains debated. This work aimed to investigate this association accounting for genetic polymorphisms of the Th2 pathway cytokines (IL4, IL10, IL13, and IL4R).

METHODS

Analyses were based on the French case-control study ESTELLE (2010-2011). The complete sample included 629 ALL cases and 1421 population-based controls frequency-matched on age and gender. The child's medical history was collected through standardized maternal interview. Biological samples were collected, and genotyping data were available for 411 cases and 704 controls of European origin. Odds ratios (OR) were estimated using unconditional regression models adjusted for potential confounders.

RESULTS

In the complete sample, a significant inverse association was observed between ALL and reported history of allergic rhinitis or sinusitis (OR = 0.65 [0.42-0.98]; P = 0.04), but there was no obvious association with allergies overall. There was an interaction between genetic polymorphisms in IL4 and IL4R (P_{interaction =} 0.003), as well as a gene-environment interaction between IL4R-rs1801275 and a reported history of asthma (IOR = 0.23; P_int  = 0.008) and eczema (IOR = 0.47; P_int  = 0.06). We observed no interaction with the candidate polymorphisms in IL4 and IL13.

CONCLUSION

These results suggest that the association between allergic symptoms and childhood ALL could be modified by IL4R-rs1801275, and that this variant could also interact with a functional variant in IL4 gene. Although they warrant confirmation, these results could help understand the pathological mechanisms under the reported inverse association between allergy and childhood ALL.

Can the Synergic Contribution of Multigenic Variants Explain the Clinical and Cellular Phenotypes of a Neurodevelopmental Disorder?

We describe an infant female with a syndromic neurodevelopmental clinical phenotype and increased chromosome instability as cellular phenotype. Genotype characterization revealed heterozygous variants in genes directly or indirectly linked to DNA repair: a de novo X-linked HDAC8 pathogenic variant, a paternally inherited FANCG pathogenic variant and a maternally inherited BRCA2 variant of uncertain significance. The full spectrum of the phenotype cannot be explained by any of the heterozygous variants on their own; thus, a synergic contribution is proposed. Complementation studies showed that the FANCG gene from the Fanconi Anaemia/BRCA (FA/BRCA) DNA repair pathway was impaired, indicating that the variant in FANCG contributes to the cellular phenotype. The patient’s chromosome instability represents the first report where heterozygous variant(s) in the FA/BRCA pathway are implicated in the cellular phenotype. We propose that a multigenic contribution of heterozygous variants in HDAC8 and the FA/BRCA pathway might have a role in the phenotype of this neurodevelopmental disorder. The importance of these findings may have repercussion in the clinical management of other cases with a similar synergic contribution of heterozygous variants, allowing the establishment of new genotype–phenotype correlations and motivating the biochemical study of the underlying mechanisms.

A new frontier in Fanconi anemia: From DNA repair to ribosome biogenesis

Described by Guido Fanconi almost 100 years ago, Fanconi anemia (FA) is a rare genetic disease characterized by developmental abnormalities, bone marrow failure (BMF) and cancer predisposition. The proteins encoded by FA-mutated genes (FANC proteins) and assembled in the so-called FANC/BRCA pathway have key functions in DNA repair and replication safeguarding, which loss leads to chromosome structural aberrancies. Therefore, since the 1980s, FA has been considered a genomic instability and chromosome fragility syndrome. However, recent findings have demonstrated new and unexpected roles of FANC proteins in nucleolar homeostasis and ribosome biogenesis, the alteration of which impacts cellular proteostasis. Here, we review the different cellular, biochemical and molecular anomalies associated with the loss of function of FANC proteins and discuss how these anomalies contribute to BMF by comparing FA to other major inherited BMF syndromes. Our aim is to determine the extent to which alterations in the DNA damage response in FA contribute to BMF compared to the consequences of the loss of function of the FANC/BRCA pathway on the other roles of the pathway.