Cancer prevention by aspirin in children with Constitutional Mismatch Repair Deficiency (CMMRD)

Constitutional Mismatch Repair Deficiency Syndrome as a Cause of Numerous Malignancies in a Teenage Patient-A Case Report

Constitutional mismatch repair deficiency syndrome is a genetic disorder resulting from a biallelic mutation in one of the following genes: MLH1, MSH2, MSH6, or PMS2. Individuals with constitutional mismatch repair deficiency are highly predisposed to develop both hematological and solid cancers in childhood, particularly lymphoma, brain tumors, and gastrointestinal neoplasms. We report a case of a boy diagnosed with B-cell acute lymphoblastic leukemia at the age of 3. In 2013, at the age of 6, head magnetic resonance imaging revealed hamartoma and astrocytoma lesions in the central nervous system. Two years after treatment completion, a diagnosis of precursor T-cell lymphoblastic lymphoma, accompanied by the vena cava syndrome, was established and treated accordingly. During treatment, a genetic test using Sanger sequencing was performed-a biallelic mutation in the MSH6 gene was detected. The study revealed that the mutation 17-bp c.2277-2293del. was inherited from the patient's mother. The second mutation, 5-bp c.1135_1139delAGAGA, developed inpatient de novo. At the age of 14, the diagnosis of isolated bone marrow relapse of acute lymphoblastic leukemia B-cell type was established. Due to the almost exceeded total dose of anthracyclines, the patient's treatment included blinatumomab, and subsequently, he was qualified for allogeneic hematopoietic cell transplantation. The patient remains in complete remission for 11 months after allogeneic hematopoietic stem cell transplantation under the care of the transplant center.

An evolutionary explanation for antibiotics’ association with increased colon cancer risk

 

More than 10 studies have confirmed the association of antibiotic overuse with colorectal cancer. The exact cause is unknown, but most authors hypothesize that disturbance of colon microbiota is the main culprit. In this commentary, an evolutionary explanation is proposed. It is well known that antibiotics can induce antibiotic resistance in bacteria through selection of mutators—DNA mismatch repair deficient (dMMR) strains. Mutators have an increased survival potential due to their high mutagenesis rate. Antibiotics can also cause stress in human cells. Selection of dMMR colon cells may be advantageous under this stress, mimicking selection of bacterial mutators. Concomitantly, mismatch repair deficiency is a common cause of cancer, this may explain the increased cancer risk after multiple cycles of oral antibiotics. This proposed rationale is described in detail, along with supporting evidence from the peer-reviewed literature and suggestions for testing hypothesis validity. Treatment schemes could be re-evaluated, considering toxicity and somatic selection mechanisms.

Lay Summary

The association of antibiotics with colon cancer is well established but of unknown cause. Under an evolutionary framework, antibiotics may select for stress-resistant cancerous cells that lack mechanisms for DNA mismatch repair (MMR). This mimics the selection of antibiotic resistant ‘mutators’—MMR-deficient micro-organisms—highly adaptive due to their increased mutagenesis rate.

Acetylsalicylic acid suppression of the PI3K pathway as a novel medical therapy for head and neck lymphatic malformations

OBJECTIVES

Head and neck lymphatic malformations (HNLM) are caused by gain-of-function somatic mutations in PIK3CA. Acetylsalicylic acid (ASA/aspirin) is thought to limit growth in PIK3CA-mutated neoplasms through PI3K pathway suppression. We sought to determine if ASA could be beneficial for HNLM.

METHODS

Retrospective case series of patients (0-18 years) offered ASA (3-5 mg/kg/day) for HNLM treatment (2010-2018). Clinical and treatment characteristics, patient-reported symptom improvement, medication tolerance, compliance, and complications were recorded. Treatment response was determined by change in patient/caregiver-reported symptoms, or HNLM size [complete (resolved), partial (decreased), or stable].

RESULTS

Fifty-three patients were offered ASA, 23 (43%) accepted (median age 10 years, IQR 6-14). Compared to patients who declined, patients receiving ASA were more likely to have extensive malformations: ex-utero intrapartum treatment procedure, bilateral malformations, oral cavity location, ≥2 invasive treatments, or tracheotomy (p < 0.05). All patients with tissue available had PIK3CA mutations (13/23). Treatment indications included oral pain/blebs (12, 52%), recurrent pain/swelling (6, 26%), or sudden/persistent swelling (5, 22%). Treatment plan was commonly one 81 mg tablet daily (19, 83%) for 3-12 months (8, 42%). Therapeutic adherence was reported by 18 patients (78%). Symptoms improved in 18 patients [78%; decreased pain (9, 39%) and swelling (8, 35%)]. Treatment resulted in partial (14, 61%) or complete response (4, 17%). Three patients developed oral bleb bleeding, which resolved with medication discontinuation.

CONCLUSION

ASA seems to be a well-tolerated, low-risk medication for HNLM treatment. This pilot study suggests that it often improves symptoms and reduces HNLM size. Further prospective, randomized studies are warranted to comprehensively assess indications, safety, and efficacy.

LEVEL OF EVIDENCE

Level 4.

Cancer predisposition in pediatric neuro-oncology-practical approaches and ethical considerations

A genetic predisposition to tumor development can be identified in up to 10% of pediatric patients with central nervous system (CNS) tumors. For some entities, the rate of an underlying predisposition is even considerably higher. In recent years, population-based approaches have helped to further delineate the role of cancer predisposition in pediatric oncology. Investigations for cancer predisposition syndrome (CPS) can be guided by clinical signs and family history leading to directed testing of specific genes. The increasingly adopted molecular analysis of tumor and often parallel blood samples with multi-gene panel, whole-exome, or whole-genome sequencing identifies additional patients with or without clinical signs. Diagnosis of a genetic predisposition may put an additional burden on affected families. However, information on a given cancer predisposition may be critical for the patient as potentially influences treatment decisions and may offer the patient and healthy carriers the chance to take part in intensified surveillance programs aiming at early tumor detection. In this review, we discuss some of the practical and ethical challenges resulting from the widespread use of new diagnostic techniques and the most important CPS that may manifest with brain tumors in childhood.

Diagnostic challenges in a CMMRD patient with a novel mutation in the PMS2 gene: a case report

Background

Constitutional mismatch repair deficiency (CMMRD) is a rare autosomal recessive condition, which is caused by biallelic mutations in mismatch repair genes: MSH2, MLH1, MSH6, and PMS2.

Case presentation

We reported a unique case of an 11-year-old Chinese girl with colorectal polyposis and café-au-lait macules who had no obvious family history of Lynch syndrome-associated tumors, followed by brain gliomas and colorectal carcinoma five years later. The diagnosis of CMMRD was based on gene sequencing analysis showing a homozygous deletion NM_00535.5:c.1577delA (p.Asp526fs) in exon 11 of the PMS2 gene. Although the patient underwent surgery and radiation therapy, and close surveillances including radiological, endoscopic and hematological screening have been recommended, she died of the exacerbation of neurological symptoms at the age of 18.

Conclusions

We identified a novel homozygous deletion in the PMS2 gene in a CMMRD patient with complex clinical features.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-021-01031-9.

Challenges of Neoantigen Targeting in Lynch Syndrome and Constitutional Mismatch Repair Deficiency Syndrome

Lynch syndrome (LS) and constitutional mismatch repair deficiency (CMMRD) are hereditary disorders characterised by a highly increased risk of cancer development. This is due to germline aberrations in the mismatch repair (MMR) genes, which results in a high mutational load in tumours of these patients, including insertions and deletions in genes bearing microsatellites. This generates microsatellite instability and cause reading frameshifts in coding regions that could lead to the generation of neoantigens and opens up avenues for neoantigen targeting immune therapies prophylactically and therapeutically. However, major obstacles need to be overcome, such as the heterogeneity in tumour formation within and between LS and CMMRD patients, which results in considerable variability in the genes targeted by mutations, hence challenging the choice of suitable neoantigens. The machine-learning methods such as NetMHC and MHCflurry that predict neoantigen- human leukocyte antigen (HLA) binding affinity provide little information on other aspects of neoantigen presentation. Immune escape mechanisms that allow MMR-deficient cells to evade surveillance combined with the resistance to immune checkpoint therapy make the neoantigen targeting regimen challenging. Studies to delineate shared neoantigen profiles across patient cohorts, precise HLA binding algorithms, additional therapies to counter immune evasion and evaluation of biomarkers that predict the response of these patients to immune checkpoint therapy are warranted.

Pathological Features of Tumors of the Nervous System in Hereditary Cancer Predisposition Syndromes: A Review

Hereditary cancer predisposition syndromes (HCS) become more recognizable as the knowledge about them expands, and genetic testing becomes more affordable. In this review, we discussed the known HCS that predispose to central and peripheral nervous system tumors. Different genetic phenomena were highlighted, and the important cellular biological alterations were summarized. Genetic mosaicism and germline mutations are features of HCS, and recently, they were described in normal population and as modifiers for the genetic landscape of sporadic tumors. Description of the tumors arising in these conditions was augmented by representative cases explaining the main pathological findings. Clinical spectrum of the syndromes and diagnostic criteria were tabled to outline their role in defining these disorders. Interestingly, precision medicine has found its way to help these groups of patients by offering targeted preventive measures. Understanding the signaling pathway alteration of mammalian target of rapamycin (mTOR) in tuberous sclerosis helped introducing mTOR inhibitors as a prophylactic treatment in these patients. More research to define the germline genetic alterations and resulting cellular signaling perturbations is needed for effective risk-reducing interventions beyond prophylactic surgeries.

Metachronous Wilms Tumor, Glioblastoma, and T-cell Leukemia in an Child With Constitutional Mismatch Repair Deficiency syndrome due to Novel Mutation in MSH6 (c.2590G>T)

Constitutional mismatch repair deficiency (CMMRD) is an autosomal recessively inherited childhood cancer predisposition syndrome results from biallelic germline mutations affecting the key DNA mismatch repair gene: MLH1, MSH2, MSH6, or PMS2. CMMRD is associated with a high risk of developing early onset of central nervous system tumors, hematologic, and intestinal tract tumors. Clinical manifestations, genetic screening, and cancer prevention strategies are limited. In this report we present a patient with metachronous Wilms tumor, glioblastoma, and acute T-cell lymphoblastic leukemia. He had cutaneous features of neurofibromatosis type 1 (NF1). Molecular testing revealed a novel homozygous mutation in MSH6 (c.2590G>T; p.G864*) that has not been reported previously. CMMRD should be considered in patients with cutaneous features similar to NF1 if tumor is found other than expected tumors in NF, early onset cancer, and strong family history of cancer.

Predisposition to cancer in children and adolescents

Childhood malignancies are rarely related to known environmental exposures, and it has become increasingly evident that inherited genetic factors play a substantial causal role. Large-scale sequencing studies have shown that approximately 10% of children with cancer have an underlying cancer predisposition syndrome. The number of recognised cancer predisposition syndromes and cancer predisposition genes are constantly growing. Imaging and laboratory technologies are improving, and knowledge of the range of tumours and risk of malignancy associated with cancer predisposition syndromes is increasing over time. Consequently, surveillance measures need to be constantly adjusted to address these new findings. Management recommendations for individuals with pathogenic germline variants in cancer predisposition genes need to be established through international collaborative studies, addressing issues such as genetic counselling, cancer prevention, cancer surveillance, cancer therapy, psychological support, and social-ethical issues. This Review represents the work by a group of experts from the European Society for Paediatric Oncology (SIOPE) and aims to summarise the current knowledge and define future research needs in this evolving field.

Position paper: Challenges and specific strategies for constitutional mismatch repair deficiency syndrome in low-resource settings

Germline biallelic mutations in one of the mismatch repair genes, mutS homolog 2, mutS homolog 6, mutL homolog 1, or postmeiotic segregation increased 2, result in one of the most aggressive cancer syndromes in humans termed as constitutional mismatch repair deficiency (CMMRD). Individuals with CMMRD are affected with multiple tumors arising from multiple organs during childhood, and these individuals rarely reach adulthood without specific interventions. The most common tumors observed are central nervous system, hematological, and gastrointestinal malignancies. The incidence of CMMRD is expected to be high in low-resource settings due to a high rate of consanguinity in these regions, and it is thought to be underrecognized and consequently underdiagnosed. This position paper is therefore important to provide a summary of the current situation, and to highlight the necessity of increasing awareness, diagnostic criteria, and surveillance to improve survival for patients and family members.

Constitutional mismatch repair deficiency-associated brain tumors: report from the European C4CMMRD consortium

Background

Malignant brain tumors (BT) are among the cancers most frequently associated with constitutional mismatch repair deficiency (CMMRD), a rare childhood cancer predisposition syndrome resulting from biallelic germline mutations in mismatch repair genes. This study analyzed data from the European “Care for CMMRD” (C4CMMRD) database to describe their clinical characteristics, treatments, and outcome with the aim of improving its diagnosis/treatment.

Methods

Retrospective analysis of data on patients with CMMRD and malignant BT from the C4CMMRD database up to July 2017.

Results

Among the 87 registered patients, 49 developed 56 malignant BTs: 50 high-grade gliomas (HGG) (with giant multinucleated cells in 16/21 histologically reviewed tumors) and 6 embryonal tumors. The median age at first BT was 9.2 years [1.1–40.6], with nine patients older than 18. Twenty-seven patients developed multiple malignancies (including16 before the BT). Most patients received standard treatment, and eight patients immunotherapy for relapsed HGG. The 3- and 5-year overall survival (OS) rates were 30% (95% CI: 19–45) and 22% (95% CI: 12–37) after the first BT, with worse prognosis for HGG (3-year OS = 20.5%). Six patients were alive (median follow-up 2.5 years) and 43 dead (38 deaths, 88%, were BT-related). Other CMMRD-specific features were café-au-lait macules (40/41), multiple BTs (5/15), developmental brain anomalies (11/15), and consanguinity (20/38 families).

Conclusions

Several characteristics could help suspecting CMMRD in pediatric malignant BTs: giant cells on histology, previous malignancies, parental consanguinity, café-au-lait macules, multiple BTs, and developmental brain anomalies. The prognosis of CMMRD-associated BT treated with standard therapies is poor requiring new therapeutic up-front approaches.

Paediatric systemic lupus erythematosus as a manifestation of constitutional mismatch repair deficiency

Biallelic mutations in any of the four mismatch repair genes MSH2, MSH6, MLH1 and PMS2 result in one of the most aggressive childhood cancer predisposition syndromes, termed constitutional mismatch repair deficiency (CMMRD) syndrome. In addition to a very high tumour risk, the CMMRD phenotype is often characterised by the presence of signs reminiscent of neurofibromatosis type 1. Although paediatric systemic lupus erythematosus (pSLE) has been reported so far in three patients with CMMRD, it has not been considered a diagnostic feature of the syndrome. We report here two additional female patients with pSLE and CMMRD due to biallelic pathogenic variants in MSH6 Hence, there are a total of five out of approximately 200 (2.5%) currently reported patients with CMMRD that also have pSLE, suggesting pSLE should raise the suspicion of a diagnosis of CMMRD, especially if supported by additional indicative features.

Hereditary Tumor Syndromes with Skin Involvement

Cutaneous findings that appear in childhood may be the first sign of a hereditary tumor syndrome. Early detection of genodermatoses allows the patient and at-risk family members to be screened for associated malignancies. This article provides a brief description of the pathogenesis and clinical manifestations of various inherited disorders with skin involvement, along with treatment updates. Advances in molecular-based therapy have spurred development of novel treatment methods for various genodermatoses such as xeroderma pigmentosum (XP) and Gorlin-Goltz syndrome. Further studies are needed to better assess the efficacy of many of these new treatment options.

RETRACTED: IP1867B suppresses the insulin-like growth factor 1 receptor (IGF1R) ablating epidermal growth factor receptor inhibitor resistance in adult high grade gliomas

This article has been retracted at the request of the Editor-in-Chief due to concerns regarding the legitimacy of images and data presented in the paper. Though a corrigendum (Can. Lett. Vol. 469, 2020, pages 524-535) was previously published to address some of these concerns, this corrigendum has also been found to contain errors and therefore cannot stand. Specific concerns are listed below. The Editor and Publisher received a letter from the University of Portsmouth alerting us to an investigation into alleged research misconduct. The University concluded their investigation with external experts and determined that misconduct did take place in relation to the research involved in this paper. Upon our separate investigation, it has been determined that the paper headline relies on showing that there was considerable reduction of IGF1R, IL6R and EGFR post treatment in all cell lines. During review, it was determined that this cannot be concluded from the presented data. For example, in SEBTA-003 the EGFR levels go up and there is no difference in IGFR1. It is apparent from Fig 4d that in the SEBTA-003 cell line the EGFR level does not go down, which is stated in the Results section on page 32, it is rather going up. The data for IGFR1 are inconclusive and there are concerns regarding the blot. The general implications would be that the effects of the drug IP1867B does not seem to be the same for all tested cell lines, and this should have been discussed in detail by the authors. Additionally, in subsequent experiments (Fig. 4g and h) the SEBTA-003 cell line (no reduction of EGFR, rather increased expression) and the other 3 cell lines (reduction of EGFR) show similar responses. This is particularly evident in Fig. 4g: Two cell lines are compared, SEBTA-003 (increased EGFR expression) and UP-029 (decreased EGFR expression), both behave similarly after exposure to drugs. The corrigendum (https://doi.org/10.1016/j.canlet.2019.10.002) issue is with respect to the Supplemental Figure 6i EGFR, particularly panel IP1867B. The Corrigendum states that the left part is a cut out of the very right part. If so, the bands for IP1867B should show the same staining pattern - but they do not. Also, in the Corrigendum, there are incorrect mentions between day 14 in the Figure and day 19 in the Figure legend. All authors were informed of the retraction in advance. Drs. Pritchard and Duckworth agreed to the retraction. The corresponding author, Dr Hill, did not agree to the retraction. No response had been received from Drs. Mihajluk, Simms, Reay, Madureira, Howarth, Murray, Nasser and Pilkinton at the time of the retraction being published.

A sensitive and scalable microsatellite instability assay to diagnose constitutional mismatch repair deficiency by sequencing of peripheral blood leukocytes

Constitutional mismatch repair deficiency (CMMRD) is caused by germline pathogenic variants in both alleles of a mismatch repair gene. Patients have an exceptionally high risk of numerous pediatric malignancies and benefit from surveillance and adjusted treatment. The diversity of its manifestation, and ambiguous genotyping results, particularly from PMS2, can complicate diagnosis and preclude timely patient management. Assessment of low-level microsatellite instability in nonneoplastic tissues can detect CMMRD, but current techniques are laborious or of limited sensitivity. Here, we present a simple, scalable CMMRD diagnostic assay. It uses sequencing and molecular barcodes to detect low-frequency microsatellite variants in peripheral blood leukocytes and classifies samples using variant frequencies. We tested 30 samples from 26 genetically-confirmed CMMRD patients, and samples from 94 controls and 40 Lynch syndrome patients. All samples were correctly classified, except one from a CMMRD patient recovering from aplasia. However, additional samples from this same patient tested positive for CMMRD. The assay also confirmed CMMRD in six suspected patients. The assay is suitable for both rapid CMMRD diagnosis within clinical decision windows and scalable screening of at-risk populations. Its deployment will improve patient care, and better define the prevalence and phenotype of this likely underreported cancer syndrome.

Constitutional mismatch repair deficiency as a differential diagnosis of neurofibromatosis type 1: consensus guidelines for testing a child without malignancy

Constitutional mismatch repair deficiency (CMMRD) is a rare childhood cancer predisposition syndrome caused by biallelic germline mutations in one of four mismatch-repair genes. Besides very high tumour risks, CMMRD phenotypes are often characterised by the presence of signs reminiscent of neurofibromatosis type 1 (NF1). Because NF1 signs may be present prior to tumour onset, CMMRD is a legitimate differential diagnosis in an otherwise healthy child suspected to have NF1/Legius syndrome without a detectable underlying NF1/SPRED1 germline mutation. However, no guidelines indicate when to counsel and test for CMMRD in this setting. Assuming that CMMRD is rare in these patients and that expected benefits of identifying CMMRD prior to tumour onset should outweigh potential harms associated with CMMRD counselling and testing in this setting, we aimed at elaborating a strategy to preselect, among children suspected to have NF1/Legius syndrome without a causative NF1/SPRED1 mutation and no overt malignancy, those children who have a higher probability of having CMMRD. At an interdisciplinary workshop, we discussed estimations of the frequency of CMMRD as a differential diagnosis of NF1 and potential benefits and harms of CMMRD counselling and testing in a healthy child with no malignancy. Preselection criteria and strategies for counselling and testing were developed and reviewed in two rounds of critical revisions. Existing diagnostic CMMRD criteria were adapted to serve as a guideline as to when to consider CMMRD as differential diagnosis of NF1/Legius syndrome. In addition, counselling and testing strategies are suggested to minimise potential harms.

Constitutional mismatch repair-deficiency: current problems and emerging therapeutic strategies

Mismatch repair (MMR) proteins remove errors from newly synthesized DNA, improving the fidelity of DNA replication. A loss of MMR causes a mutated phenotype leading to a predisposition to cancer. In the last 20 years, an increasing number of patients have been described with biallelic MMR gene mutations in which MMR defects are inherited from both parents. This leads to a syndrome with recessive inheritance, referred to as constitutional mismatch repair-deficiency (CMMRD). CMMRD is a rare childhood cancer predisposition syndrome. The spectrum of CMMRD tumours is broad and CMMRD-patients possess a high risk of multiple cancers including hematological, brain and intestinal tumors. The severity of CMMRD is highlighted by the fact that patients do not survive until later life, emphasising the requirement for new therapeutic interventions. Many tumors in CMMRD-patients are hypermutated leading to the production of truncated protein products termed neoantigens. Neoantigens are recognized as foreign by the immune system and induce antitumor immune responses. There is growing evidence to support the clinical efficacy of neoantigen based vaccines and immune checkpoint inhibitors (collectively referred to as immunotherapy) for the treatment of CMMRD cancers. In this review, we discuss the current knowledge of CMMRD, the advances in its diagnosis, and the emerging therapeutic strategies for CMMRD-cancers.