Early-onset Malignancies Research Articles

Molecular insights into TP53 mutation (p. Arg267Trp) and its connection to Choroid Plexus Carcinomas and Li-Fraumeni Syndrome.

Choroid plexus carcinomas (CPCs) are rare malignant tumors primarily affecting pediatric patients and often co-occur with Li-Fraumeni Syndrome (LFS), an inherited predisposition to early-onset malignancies in multiple organ systems. LFS is closely linked to TP53 mutations, with germline TP53 gene mutations present in approximately 75% of Li-Fraumeni syndrome families and 25% of Li-Fraumeni-like syndrome families. Individuals with TP53 mutations also have an elevated probability of carrying mutations in BRCA1 and BRCA2 genes. To investigate the structural and functional implications of the TP53: 799C > T, p. (Arg267Trp) missense mutation, initially identified in a Saudi family, and understand its impact on TP53 functionality and related intermolecular interactions. Computational analyses were conducted to examine the structural modifications resulting from the TP53: 799C > T, p. (Arg267Trp) mutation. These analyses focused on the mutation's impact on hydrogen bonding, ionic interactions, and the specific interaction with Cell Cycle and Apoptosis Regulator 2 (CCAR2), as annotated in UniProt. The study revealed that the native Arg267 residue is critical for a salt bridge interaction with glutamic acid at position 258. The mutation-induced charge alteration has the potential to disrupt this ionic bonding. Additionally, the mutation is located within an amino acid region crucial for interaction with CCAR2. The altered properties of the amino acid within this domain may affect its functionality and disrupt this interaction, thereby impacting the regulation of catalytic enzyme activity. Our findings highlight the intricate intermolecular interactions governing TP53 functionality. The TP53: 799C > T, p. (Arg267Trp) mutation causes structural modifications that potentially disrupt critical ionic bonds and protein interactions, offering valuable insights for the development of targeted mutants with distinct functional attributes. These insights could inform therapeutic strategies for conditions associated with TP53 mutations.

(384) - Early Onset Malignancy in the First-Year After Heart Transplantation

(384) - Early Onset Malignancy in the First-Year After Heart Transplantation

A FANCA mutation carrier with enhanced toxicity to cancer directed treatment - A case report and review of literature

Chemotherapy and radiotherapy are backbones of cancer treatment. Genome instability syndromes are rare but an essential factor to be identified early in the treatment of malignancies. It can lead to the occurrence of multiple malignancies and impede treatment due to undue hypersensitivity, leading to extreme and often fatal toxicities. We, hereby, report a case of a middle-aged lady who was diagnosed with a carcinoma of the head and neck and planned for treatment with neoadjuvant chemotherapy followed by surgery or chemoradiation. However, she developed severe toxicity to all forms of treatment for cancer. Her gene-based panel screening test revealed a Fanconi anaemia, complementation group A (FANCA) gene abnormality which is associated with an autosomal recessive mode of inheritance. This case outlines the importance of considering the possibility and a high index of suspicion of a hereditary basis in cases of relatively early-onset malignancy before defining an oncological treatment strategy. The paucity of data except for case reports limits evidence-based management in such cases and requires a collective effort for treatment.

Malignancy in Ataxia Telangiectasia (A-T)

RationaleAtaxia telangiectasia (A-T) is an autosomal recessive DNA repair disorder caused by biallelic mutations in the ATM gene. Clinical features include immunodeficiency, neurodegeneration and cancer predisposition. About 25% of A-T patients will develop early onset malignancies, which are difficult to treat given hypersensitivity to radiation and radiomimetic drugs. Cancer is a leading cause of death in A-T patients. MethodsWe queried the Johns Hopkins A-T Clinical Center database for patients with a confirmed cancer diagnosis. A total of 76 out of 505 patients seen at the clinic from 1995 to the present were identified. Patients were characterized by demographics, age at cancer diagnosis, A-T phenotype (classic versus atypical), ATM mutation, type of malignancy, cancer therapy, therapy modifications, therapy-associated toxicity, and two-year event free survival. ResultsWe found 56 hematologic malignancies with an average cancer diagnosis age of 14.1 years. Among patients < 18 years of age, hematological malignancies were predominant (91%), whereas among patients >18 years old, solid tumors were common (61%). 34 (60.7%) cases were non-Hodgkin lymphoma, 15 (26.7%) leukemias with T cell predominance, and 7 (12.5%) Hodgkin's lymphomas. There were 24 solid tumors in 22 patients, with an average cancer diagnosis age of 25.3 years; 9 (38%) gastrointestinal, 7 (29%) skin, 3 (13%) breast, 2 (8%) thyroid, and 1 each lung, gynecologic and parotid cancer. We found that 76% of our malignancy cohort died of cancer or therapy complications. ConclusionsWe characterized cancers in the world's largest A-T cohort with the future goal of providing improved malignancy screening and developing research protocols for standardized treatment.

Malignancy in Ataxia-Telangiectasia (A-T)

A-T is an autosomal recessive DNA repair disorder caused by biallelic mutations in the ATM gene. Clinical features include immunodeficiency, neurodegeneration and cancer predisposition. About 25% of A-T patients will develop early onset malignancies, which are difficult to treat given hypersensitivity to radiation and radiomimetic drugs. Cancer is a leading cause of death in A-T patients.

Li-Fraumeni syndrome: A case report

Introduction. Li-Fraumeni syndrome (LFS) is a hereditary familial predisposition to a wide range of certain, often rare malignant diseases. Patients also have an increased risk of developing secondary and even tertiary malignancies throughout their lifetime. The most common malignancies are soft-tissue and bone sarcomas, breast cancer, brain tumors, adrenocortical carcinoma, and acute leukemia. The syndrome is inherited as an autosomal dominant disorder. In most families with LFS, germline mutations of the tumor protein have been identified on the TP53 gene. To our knowledge, this is the second case report of LFS that has been reported in our country so far. Case report. We present five members of the same family with malignant diseases typical for LFS. A woman at the age of 21 had recurrent astrocytoma and mediastinal liposarcoma. Her older sister had rhabdomyosarcoma and liver cancer and died at the age of 18. The mother of their father was diagnosed with breast cancer at the age of 45, and she died at the age of 52. The father?s sister had osteosarcoma and died before the age of 40. The father was diagnosed with lung adenocarcinoma at the age of 49, two years after the death of his second daughter. Genetic analysis identified a pathogenic, heterozygous germline mutation of the TP53 gene. He also has a third, 8-year-old daughter for whom he denied testing for LFS. Conclusion. Genetic analysis for LFS of all family members is required in patients with rare and multiple malignancies but also frequent and early onset malignancies in the family. Screening for the detection of early cancer manifestation is the key to prolonged survival in people with LFS.

Abstract 1428: DNA methylation predicts early onset of primary tumor in patients with Li-Fraumeni syndrome

Abstract Background: Li-Fraumeni syndrome (LFS) is an autosomal dominant cancer predisposition syndrome. Approximately 80% of individuals with LFS harbor a germline TP53 pathogenic variant rendering them susceptible to a wide spectrum of early-onset malignancies. A comprehensive surveillance regimen termed the ‘Toronto Protocol’, has recently been adopted for early tumor detection, demonstrating significant improvement in survival among TP53 pathogenic variant carriers. However, the protocol’s “one-size-fits-all” approach fails to consider an individual patient's risk of cancer. We built a machine learning model that predicts early-onset of primary tumors in LFS by estimating the probability of cancer onset before the age of six years, leveraging patient peripheral blood leukocyte methylation profiles. Methods: We built a gradient-boosted tree model to predict the probability of cancer onset before the age of six using methylation data from 288 TP53 pathogenic variant carriers. An external test set of 82 TP53 pathogenic variant carriers was used to validate our model. To increase the signal-to-noise ratio, methylation probes associated with TP53 status were retained and probes associated with aging were removed. In our study, we were primarily interested in minimizing the false negative rate (i.e. to reduce the number of patients who developed cancer before the age of six but were undetected by our algorithm. Findings: We correctly predicted whether the first tumor will occur before the age of six with an accuracy of 79% in our external test set. Importantly, our model classified 90% of the patients that developed cancer prior to the age of six correctly. In addition, 81% of the individuals without cancer in the external test set were predicted correctly. Interpretation: Our tool provides additional value to clinicians in stratifying patients into low- or high-risk groups of developing early-onset malignancies, and helps inform rational use of clinical surveillance tools for early cancer detection, with the ultimate aim to improve overall patient outcomes. Citation Format: Vallijah Subasri, Benjamin Brew, Lauren Erdman, Tanya Guha, Jordan R. Hansford, Elizabeth Cairney, Carol Portwine, Christine Elser, Jonathan L. Finlay, Kim E. Nichols, Wendy Kohlmann, Noa Alon, Ana Novokmet, Ledia Brunga, Anita Villani, Kelvin C. de Andrade, Payal P. Khincha, Sharon A. Savage, Joshua D. Schiffman, David Malkin, Anna Goldenberg. DNA methylation predicts early onset of primary tumor in patients with Li-Fraumeni syndrome [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1428.

The contribution of Lynch syndrome to early onset malignancy in Ireland

BackgroundLynch syndrome (LS) is an autosomal dominant hereditary cancer syndrome responsible for 2–4% of hereditary colorectal cancers (CRC). Mismatch repair protein deficiency (dMMR) is a characteristic feature of LS. It has been associated with a poor response to standard chemotherapy in metastatic colorectal cancer (mCRC). There is currently no LS database to monitor trends of disease in Ireland. We aim to centralise LS data in Ireland to assess the burden of LS in Ireland and guide improvements in prevention and treatment of LS-associated cancer.MethodsA retrospective review was carried out including all medical records for LS patients from two of the three cancer genetics clinics in Ireland between 2000 and 2018 was carried out. Clinicopathological data of probands (n = 57) and affected family members including demographics, mutation status, cancer diagnosis and outcome was recorded. Statistical analysis was carried out using SPSS software.ResultsFifty-seven families including three-hundred and forty-five individuals affected by cancer were identified. The most common cancers recorded were colorectal (53%), breast (12%) and endometrial (10%). One-hundred and thirty-eight confirmed carriers were identified: 65 path_MLH1 (47%), 43 path_MSH2 (31%), 11 path_MSH6 (8%), 17 path_PMS2 (12%) and two path_EPCAM (1%). Cancer type varied significantly by gene. Median age of first diagnosis was 44.5 years (range 23–81). Half of all deceased patients (n = 11) in this group died within 2.5 years of first diagnosis. These deaths were directly related to cancer in 59% of cases.ConclusionsUnder diagnosis of LS misses a powerful preventive and therapeutic opportunity. LS causes early onset dMMR cancer diagnoses with substantial societal impact. Implementation of ICBs into treatment policy for this small cohort of dMMR mCRC is an achievable therapeutic goal that may significantly improve survival. A prospective database for LS in Ireland is necessary to maximise prevention in this population.

Abstract B15: Investigating the contribution of mTORC1-dependent stromal signaling to cancer onset in Li-Fraumeni syndrome

Abstract In this study, we are investigating the role of stromal mTORC1 signaling in the development of malignancy in individuals with Li-Fraumeni syndrome (LFS). LFS is a cancer predisposition syndrome that is associated with germline mutations in TP53. Individuals with LFS are faced with a significant lifetime risk of developing a wide spectrum of early-onset malignancies, thus necessitating the identification of pharmacologic agents to prevent tumor onset. Inhibitors of the mTORC1 pathway, namely rapamycin and metformin, have been shown to promote lifespan extension and delay or even prevent tumor onset in LFS mouse models. These findings are unsurprising—since wild-type p53 inhibits mTORC1—yet noteworthy, since they suggest that mTORC1 signaling plays a central role in favoring tumorigenesis in LFS. mTORC1 signaling has been implicated in promoting the protumorigenic senescence-associated secretory phenotype (SASP). The SASP constitutes the release of soluble factors, such as cytokines, growth factors, and proteases from senescent cells into the microenvironment, thus promoting oncogenesis in a paracrine manner. Interestingly, an increased incidence of senescence has been reported in LFS patients, and mutant p53 has been shown to promote the secretion of a quantitatively and qualitatively more protumorigenic SASP. As such, we believe that mTORC1 signaling in LFS stromal cells favors the production and secretion of protumorigenic factors, which may induce changes in the surrounding tissue to promote development of a precancerous niche, thus favoring tumorigenesis. Our objectives are 1) to investigate the contribution of stromal cells and stromal secreted factors in favoring tumorigenesis in LFS, and 2) to investigate the role of mTORC1 signaling in favoring these altered stromal phenotypes. To address these objectives, we co-injected patient-derived LFS fibroblasts with tumor cells of a common LFS subtype (rhabdomyosarcoma [RMS]) into immunocompromised mice and observed that tumors formed from the co-injection of RMS cells with LFS fibroblasts grew to be larger than tumors formed from co-injection with non-LFS fibroblasts. To determine whether LFS fibroblasts secrete more protumorigenic cytokines than non-LFS fibroblasts, we performed protein arrays with conditioned media (CM) from fibroblast cultures and saw that LFS fibroblasts secrete markedly higher levels of protumorigenic, SASP-related cytokines. To investigate the protumorigenic effects of fibroblast secreted factors, we treated spheroids formed from tumor cells of a common LFS subtype (osteosarcoma) with CM from LFS and non-LFS fibroblast cultures. LFS fibroblast CM had a robust proproliferative effect on spheroids, while non-LFS fibroblast CM inhibited spheroid growth. Thus far, we have observed that LFS stromal constituents favor tumor cell proliferation in vitro and in vivo, and based on the current literature, we believe that mTORC1 signaling plays a role in favoring these processes. Citation Format: Camilla M. Giovino, Nish Patel, Sangeetha Paramathas, David Malkin, Ran Kafri. Investigating the contribution of mTORC1-dependent stromal signaling to cancer onset in Li-Fraumeni syndrome [abstract]. In: Proceedings of the AACR Special Conference on Targeting PI3K/mTOR Signaling; 2018 Nov 30-Dec 8; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Res 2020;18(10_Suppl):Abstract nr B15.

Prevalence of pancreaticobiliary cancers in Irish families with pathogenic BRCA1 and BRCA2 variants.

Pathogenic variants (PVs) in the BRCA1 and BRCA2 genes are associated with an increased lifetime risk of pancreatic ductal adenocarcinoma (PDAC), and more recently have been associated with increased risk of biliary tract cancers (BTC). This study assessed the prevalence, age and gender distribution of PDAC/BTC cases in families known to carry a BRCA1/2 PV compared to those of the Irish population. A review of all families referred to a national genetics clinic from 09/11/1997 to 01/06/2018 was performed. The BOADICEA algorithm was used to estimate the probability that an untested relative of a known BRCA1/2 PV carrier with PDAC was a carrier. We reviewed 3252 family pedigrees, 1193 contained a proband who underwent testing for BRCA1/2 based on Manchester score ≥ 15. Among 128 BRCA2 PV-positive families, 27 (21%) contained a 1st/2nd/3rd-degree relative with PDAC, while of 116 BRCA1 PV-positive families, 11 (9%) contained a 1st/2nd/3rd-degree relative with PDAC. Within these 38 families, 25 patients with PDAC had ≥ 50% likelihood of being a BRCA1/2 PV carrier. This cohort had a median age at diagnosis of 55years (range 33-75), with a mean (55years) lower than 8364 patients with PDAC identified through the National Cancer Registry of Ireland (71years, p < 0.0001). Six BRCA2 positive (5%) and 2 BRCA1 positive pedigrees (2%) included an individual with BTC; median age at diagnosis was 65years (range 33-99). PDAC and BTC are prevalent in Irish families harbouring a BRCA2 PV and are associated with early-onset malignancy. This supports current guidelines recommending universal germline testing for PDAC patients.

Abstract 2032: Investigating the contribution of mTORC1-dependent signaling in the microenvironment to cancer onset in Li-Fraumeni syndrome

Abstract We are investigating the role of stromal mTORC1 signaling in the development of malignancy in individuals with Li-Fraumeni Syndrome (LFS). LFS is a hereditary cancer predisposition syndrome that is associated with germline mutations in TP53. Individuals with LFS are faced with a significant lifetime risk of developing a wide spectrum of early-onset malignancies, thus necessitating the identification of pharmacologic agents to prevent tumour onset. Chemical inhibitors of the mTORC1 pathway have been shown to promote lifespan extension and delay or even prevent tumour onset in LFS mouse models. These findings are noteworthy, since they suggest that mTORC1 signaling plays a central role in favoring tumorigenesis in LFS. mTORC1 signaling has been implicated in promoting the pro-tumorigenic senescence-associated secretory phenotype (SASP). The SASP constitutes the release of soluble factors, such as cytokines, growth factors, and proteases from senescent cells into the microenvironment, thus promoting oncogenesis in a paracrine manner. Mutant p53 has also been shown to promote the secretion of a variety of pro-tumorigenic factors from various cell types. We believe that mTORC1 signaling in LFS stromal cells favors the production and secretion of pro-tumorigenic factors, which may induce changes in the surrounding tissue to promote development of a precancerous niche, thus favoring tumorigenesis. Our objectives are to investigate the contribution of stromal cells and stromal secreted factors in favoring tumorigenesis in LFS, and to investigate the role of mTORC1 signaling in favoring these altered stromal phenotypes. To determine whether patient-derived LFS fibroblasts with TP53 mutations secrete more pro-tumorigenic cytokines than non-LFS fibroblasts, we performed protein arrays with conditioned media (CM) from fibroblast cultures. We saw that LFS fibroblasts secrete markedly higher levels of pro-tumorigenic, SASP-related cytokines. Next, we treated spheroids formed from cancer cells of a common LFS subtype (osteosarcoma) with CM from LFS and non-LFS fibroblast cultures. LFS fibroblast CM had a robust pro-proliferative effect on spheroids, while non-LFS fibroblast CM inhibited spheroid growth. To further address these aims in vivo, we co-injected LFS fibroblasts with cancer cells of a common LFS subtype [rhabdomyosarcoma (RMS)] into Nude mice. We found that tumours formed from the co-injection of RMS cells with LFS fibroblasts grew to be larger than tumours formed from co-injection with non-LFS fibroblasts. Thus far, we have observed that LFS stromal constituents favor cancer cell proliferation in vitro and in vivo. We are currently investigating the role that mTORC1 signaling plays in these processes by repeating these studies following chemical and genetic perturbation of mTORC1 signaling in the LFS fibroblasts. Citation Format: Camilla Giovino, Nish Patel, Sangeetha Paramathas, Gaetano Zafarana, Ran Kafri, David Malkin. Investigating the contribution of mTORC1-dependent signaling in the microenvironment to cancer onset in Li-Fraumeni syndrome [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2032.

Skewed B cell receptor repertoire and reduced antibody avidity in patients with DOCK8 deficiency.

DOCK8 immunodeficiency syndrome (DIDS) is a combined immunodeficiency characterized by recurrent viral infections, severe atopy and early onset malignancy. Immunological abnormalities include lymphopenia, CD8+ T-cell cytoskeleton dysfunction, defective B cell memory and variable serum immunoglobulin levels. Here, we analyse the B cell receptor repertoire (BCR) characteristics and antibody avidity of four DIDS patients, attempt to understand the dysregulated humoral immunity in DIDS patients with a normal antibody titre and suggest a scientific basis for intravenous immunoglobulin (IVIG) replacement therapy for these patients. We analysed BCR characteristics, including somatic hypermutation (SHM) frequency, using deep sequencing of multiplex PCR products derived from BCR heavy chain CDR3 regions from DIDS patients and controls. The antibody avidity of human tetanus and hemophilus influenza B antibodies was determined by ELISA using thiocyanate elution. IVIG replacement treatment and infection conditions were investigated retrospectively. We found skewing of the BCR repertoire and decreased antibody avidity in patients with DIDS. DIDS patients had fewer negatively charged amino acids than healthy controls. The SHM frequency of the IGHV3 gene was lower in patients with DIDS. Patients received regular IVIG therapy, resulting in fewer and less severe infections. We conclude that although IgG levels are normal in most DIDS patients, IVIG replacement therapy is still necessary.

Prevalence of pancreaticobiliary cancer in Irish families with BRCA1 and BRCA2 mutations.

210 Background: Germline mutations in BRCA1 and BRCA2 genes are associated with pancreatic ductal adenocarcinoma (PDAC), and more recently associated with increased risk of biliary tract cancers (BTC). This study assessed the prevalence, age and gender distribution of PDAC/BTC in BRCA1/2 positive families; compared to those of the Irish population. Methods: A review of all families referred to a national genetics clinic from 09/11/1997-01/06/2018 was performed following institutional ethics board approval. Demographics including age, sex and BRCA mutation status was collected in each case of PDAC/BTC. The BOADICEA algorithm was used to estimate the probability that an untested relative of a known BRCA1/2 mutation carrier with PDAC was a carrier. Results: 3252 distinct family pedigrees were reviewed, of which 1193 contained a proband who underwent testing for BRCA1/2 based on Manchester score ≥ 15. Among 128 BRCA2 positive families, 27 (21%) contained a 1st/2nd or 3rd degree relative with PDAC, of 116 BRCA1 positive families, 11 (9%) contained a 1st/ 2nd or 3rd degree relative with PDAC (male: female (m:f) = 1:0.9). Of these 38 families, 25 pts with PDAC had ≥ 50% likelihood of being a mutation carrier by BODICEA analysis. This cohort had a median age at diagnosis of 55 (33-75), with a mean (55) significantly lower than that of 8364 unselected patients with PDAC identified through the National Cancer Registry Ireland (71, p &lt; 0.0001). Six BRCA2 positive (5%) and 2 BRCA1 positive pedigrees (2%) contained an individual with BTC; median age at diagnosis was 65 (33-99, m:f = 1:7). Additional pedigrees with Lynch Syndrome (n = 3), FAP (n = 1) and ATM (n = 2) and PDAC were identified. Conclusions: PDAC and BTC are prevalent in Irish families with a BRCA1/2 mutation and are associated with early onset malignancy. This consolidates evidence of PDAC and BTC as BRCA- associated cancers in the Irish population and supports current guidelines recommending universal germline testing for PDAC patients. [Table: see text]

Characterization of Pathogenic Variants and Clinical Phenotypes in 117 Japanese Fanconi Anemia Patients

Objective: Fanconi anemia (FA) is the most common inherited bone marrow failure syndrome associated with multiple congenital abnormalities and predisposition to malignancies, resulting from mutations in one of the 22 known FA genes (FANCA to W). The proteins encoded by these genes participate in DNA repair pathway (the FA pathway) for endogenous aldehyde damage. Compared to the situation in the US or Europe, the number of Japanese FA patients with genetic diagnosis was relatively limited. In this study, we reveal the genetic subtyping and the characteristics of mutated FA genes in Japanese population and clarify the genotype-phenotype correlations.Results: We studied 117 Japanese FA patients from 103 families (1996 to 2018). The diagnosis of FA was confirmed on the basis of chromosomal breakage tests and clinical features. Molecular diagnosis was obtained in 107 (91.5%) of the 117 patients through direct sequencing of FANCA and FANCG, MLPA analysis for FANCA, targeted exome sequencing (targeted-seq), and whole exome sequencing (WES) analysis (Figure 1). To provide genetic subtyping for the 10 unclassified cases, we tried to apply various technologies. Array CGH revealed large deletions in two FA-B and one FA-T cases. Whole genome sequencing and RNA-sequencing analysis identified splicing site or aberrant splicing mutations among three cases (one FA-B, one FA-C, and one FA-N). Collectively, 113 (97%) of Japanese 117 FA patients were successfully subtyped and a total of 219 mutated alleles were identified. FA-A and FA-G accounted for the disease in 58% and 25% of FA patients, respectively, whereas each of the other complementation groups accounted for less than 5% of FA cases. FANCB was the third most common complementation group (n=4) and only one FA-C case was identified in Japanese FA patients.In the 68 FA-A patients, we identified 130 mutant alleles that included 55 different FANCA variants (17 nucleotide substitutions, 16 small deletions/insertions, 12 large deletions, 1 large duplication and 9 splice site mutation). FANCA c.2546delC was the most prevalent (41/130 alleles; 32%). In the 29 FA-G patients, 57 mutant alleles were identified and seven different FANCG variants were detected. FANCG c.307+1G>C and 1066C>T accounted for most of FANCG mutant alleles (49/57; 88%) in the Japanese FA-G patients. The three hotspot mutations (FANCA c.2546delC, FANCG c.307+1G>C and c.1066C>T) existed at low prevalence (0.04-0.1%) in the whole-genome reference panel of 3554 Japanese individuals (3.5KJPN, Tohoku Megabank). Consistent with the paucity of the FA-C patients as opposed to the previous report (Blood 2000), the FANCC IVS4+4A mutation was absent in the 3.5KJPN database.We were able to examine the hematological outcomes in a subset of our cases (52 FA-A and 23 FA-G). Interestingly, the FA-G patients developed bone marrow failure (BMF) at a significantly younger age than FA-A patients (median age at onset of BMF: 3.1 years vs 5 years). Furthermore, the patients with the FANCA c.2546delC mutation had an increased risk of developing myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML), compared to FA-A patients without the mutation.In the rare complementation groups of FA, two FA-B cases with complete loss of FANCB gene and one FA-I patient with N-terminal premature termination codons revealed severe somatic abnormalities, consistent with VACTERL-H association. Two FANCD1 (BRCA2) patients and one FANCN (PALB2) patients did not experience bone marrow failure but developed early-onset malignancies (immature teratoma, T-lymphoblastic lymphoma, adenosquamous lung carcinoma, Wilms tumor).Conclusion: This is the largest series of subtyped Japanese FA patients to date and the results would be useful for future clinical management. To provide molecular diagnosis for FA in Japan, we suggest to start with PCR-direct sequencing of the three common mutations (FANCA c.2546delC, FANCG c.307+1G>C and FANCG c.1066C>T) along with MLPA assay for FANCA. These analyses would enable the identification of about 50% of the mutant alleles. For the rest of the cases, WES or targeted-seq analysis should be useful, however, large deletions and aberrant splicing need to be kept in mind. [Display omitted] DisclosuresTakaori-Kondo:Pfizer: Honoraria; Novartis: Honoraria; Celgene: Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria; Janssen Pharmaceuticals: Honoraria.

Wiskott-Aldrich syndrome gene mutations modulate cancer susceptibility in the p53± murine model

ABSTRACTThe Wiskott-Aldrich syndrome protein (WASp) is a key regulator of the actin cytoskeleton in hematopoietic cells and mutated in two severe immunodeficiency diseases with high incidence of cancer. Wiskott-Aldrich syndrome (WAS) is caused by loss-of-function mutations in WASp and most frequently associated with lymphoreticular tumors of poor prognosis. X-linked neuropenia (XLN) is caused by gain-of-function mutations in WASp and associated with acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS). To understand the role of WASp in tumorigenesis, we bred WASp+, WASp−, and WASp-XLN mice onto tumor susceptible p53+/- background and sub-lethally irradiated them to enhance tumor development. We followed the cohorts for 24 weeks and tumors were characterized by histology and flow cytometry to define the tumor incidence, onset, and cell origin. We found that p53+/-WASp+ mice developed malignancies, including solid tumors and T cell lymphomas with 71.4% of survival 24 weeks after irradiation. p53+/-WASp− mice showed lower survival rate and developed various early onset malignancies. Surprisingly, the p53+/-WASp-XLN mice developed malignancy mostly with late onset, which caused delayed mortality in this colony. This study provides evidence for that loss-of-function and gain-of-function mutations in WASp influence tumor incidence and onset.

Contribution of Lynch syndrome to early onset malignancy in Ireland.

586 Background: Lynch syndrome (LS) is an autosomal dominant hereditary cancer syndrome responsible for 2 -6% of hereditary colorectal cancers. LS is caused by germ-line mutations in mismatch repair genes (MMR): MLH1, MSH2, MSH6, PMS2 or EPCAM. This results in microsatellite instability, a phenotypic hallmark of LS-associated colorectal cancer. The aim of this study was to construct and analyse a database of Irish MMR mutation carriers. Methods: Records were from two of the three existing cancer genetics clinics in Ireland. Clinicopathological data of all probands (n=57) including names, dates of birth and death, carrier status and phenotype were recorded. Death certificates were used to confirm information regarding deceased mutation carriers. An ANOVA test was used to establish statistical significance of variations in age by gene. Length of survival based on stage was assessed using Kaplain Meier curves. Results: 345 affected individuals were identified. The most common cancers recorded were colorectal (53%), breast (12%) and endometrial (10%). 138 confirmed carriers were identified: 65 MLH1 (47%), 43 MSH2 (31%), 11 MSH6 (8%), 17 PMS2 (12%), and 2 EPCAM (1%). 22 patients have died since confirmation of Lynch Syndrome, 50% of whom died within 2.5 years of first diagnosis. All deceased carriers had at least one cancer diagnosis and 50% had developed multiple cancers. 59% of deaths were directly related to cancer. 7 of these patients had Stage 4 cancer at diagnosis. There was a significant difference in length of survival based on stage. (p=.048) Phenotype frequencies varied significantly by gene. (see table 1) Median age of first diagnosis of any cancer was 44.5 years (range 23-81). There was no difference in age at presentation by gene mutated. Conclusions: Under-diagnosis of LS misses a powerful preventive and therapeutic opportunity. LS causes early onset cancer diagnosis with substantial societal impact. A significant number of Lynch Syndrome cases have poor clinical outcomes. Genotype/Phenotype frequencies. [Table: see text]

Homozygous germ-line mutation of the PMS2 mismatch repair gene: a unique case report of constitutional mismatch repair deficiency (CMMRD)

BackgroundConstitutional mismatch repair deficiency syndrome results from bi-allelic inheritance of mutations affecting the key DNA mismatch repair genes: MLH1, MSH2, MSH6 or PMS2. Individuals with bi-allelic mutations have a dysfunctional mismatch repair system from birth; as a result, constitutional mismatch repair deficiency syndrome is characterised by early onset malignancies. Fewer than 150 cases have been reported in the literature over the past 20 years. This is the first report of the founder PMS2 mutation - NM_000535.5:c.1500del (p.Val501TrpfsTer94) in exon 11 and its associated cancers in this family.Case presentationThe proband is 30 years old and is alive today. She is of Pakistani ethnic origin and a product of consanguinity. She initially presented aged 24 with painless bleeding per-rectum from colorectal polyps and was referred to clinical genetics. Clinical examination revealed two café-au-lait lesions, lichen planus, and a dermoid cyst. Her sister had been diagnosed in childhood with an aggressive brain tumour followed by colorectal cancer. During follow up, the proband developed 37 colorectal adenomatous polyps, synchronous ovarian and endometrial adenocarcinomas, and ultimately a metachronous gastric adenocarcinoma. DNA sequencing of peripheral lymphocytes revealed a bi-allelic inheritance of the PMS2 mutation NM_000535.5:c.1500del (p.Val501TrpfsTer94) in exon 11. Ovarian tumour tissue demonstrated low microsatellite instability. To date, she has had a total abdominal hysterectomy, bilateral salpingo-oophorectomy, and a total gastrectomy. Aspirin and oestrogen-only hormone replacement therapy provide some chemoprophylaxis and manage postmenopausal symptoms, respectively. An 18-monthly colonoscopy surveillance programme has led to the excision of three high-grade dysplastic colorectal tubular adenomatous polyps. The proband’s family pedigree displays multiple relatives with cancers including a likely case of ‘true’ Turcot syndrome.ConclusionsConstitutional mismatch repair deficiency syndrome should be considered in patients who present with early onset cancer, a strong family history of cancer, and cutaneous features resembling neurofibromatosis type I. Immunohistochemistry analysis of tumour and normal tissue is sensitive and specific for identifying patients with mismatch repair deficiency and should direct DNA sequencing of lymphocytic tissue to establish a diagnosis. Microsatellite instability status appears to be of little value in identifying patients who may have constitutional mismatch repair deficiency syndrome.

Li-Fraumeni Syndrome.

Li-Fraumeni syndrome (LFS) is a cancer predisposition syndrome caused by a germline mutation of the TP53 gene on chromosome 17p13.1. It has an autosomal dominant pattern of inheritance with high penetrance. These patients have a very high lifetime cumulative risk of developing multiple malignancies and have a strong family history of early-onset malignancies. The protein p53, encoded by TP53, has a complex set of genome-preserving functions initiated during episodes of cellular stress and DNA damage. In LFS, TP53 gene mutations cause the loss of function of p53, leading to downstream events permissive for development of various malignancies throughout life. The LFS component tumors include soft tissue sarcomas, osteosarcoma, premenopausal breast cancer, brain tumors, and adrenal cortical carcinomas. Multiple types of sarcomas have been reported in association with LFS; this review article will focus on the most frequently encountered pediatric sarcomas associated with TP53 mutations.

Novel DOCK8 gene mutations lead to absence of protein expression in patients with hyper-IgE syndrome.

Autosomal recessive hyper-immunoglobulin E syndrome (AR-HIES) caused by DOCK8 defects is characterized by recurrent elevated serum IgE level, elevated peripheral eosinophil count, severe atopy, recurrent viral and bacterial infections, and early-onset malignancy. The clinical, genetic, and immunologic characteristics of DOCK8 mutations in Chinese patients have not been characterized in detail. In this research, we screened seven Chinese candidate patients for mutations within the DOCK8 gene and identified three large novel homozygous deletions and four novel point mutations by targeted deep sequencing. The homozygous deletions displayed autosomal recessive inheritance, and the point mutations were sporadic. Absence of DOCK8 protein was confirmed using flow cytometry and western blotting. Besides the typical clinical features and immunologic impairments of DIDS, proliferation of lymphocytes, cytotoxic function of NK cells, and expression of IL-10 in regulatory B cells were severely impaired in DOCK8 mutant patients which may be associated with abnormal immune responses in DIDS. These findings will contribute to the early diagnosis and treatment of DOCK8 patients.

Molecular profile of synchronous metastatic colon cancer and anaplastic thyroid cancer in a patient with Lynch Syndrome.

e22049 Background: Lynch Syndrome is an autosomal dominant disorder caused by either germline mutation in a DNA mismatch repair gene: MLH1, MSH2, MSH6, or PMS2, or epigenetic silencing of MSH2. The syndrome consists of early onset malignancies and multiplicity of cancers. Colonic malignancies predominate with the frequency and distribution of extracolonic cancers dictated by the mutated gene. Methods: A 54 year old man with a family history of Lynch Syndrome and a MSH6 mutation was found to have synchronous colonic adenocarcinomas on screening colonoscopy. Within weeks he presented with a rapidly enlarging anaplastic thyroid cancer (ATC). On PET/CT he was found to have liver metastases (biopsy confirmed as colonic) and pulmonary metastases (biopsy confirmed as ATC). Tumor tissue from his colon and thyroid was sent for FoundationOne analysis of 343 genes. Cell free circulating tumor DNA (CtDNA) was sequenced for 54 genes using Guardant360 technology with blood taken post-thyroidectomy. Results: FoundationO...