Fundamental immune-oncogenicity trade-offs define driver mutation fitness.

Missense driver mutations in cancer are concentrated in a few hotspots1. Various mechanisms have been proposed to explain this skew, including biased mutational processes2, phenotypic differences3-6 and immunoediting of neoantigens7,8; however, to our knowledge, no existing model weighs the relative contribution of these features to tumour evolution. We propose a unified theoretical 'free fitness' framework that parsimoniously integrates multimodal genomic, epigenetic, transcriptomic and proteomic data into a biophysical model of the rate-limiting processes underlying the fitness advantage conferred on cancer cells by driver gene mutations. Focusing on TP53, the most mutated gene in cancer1, we present an inference of mutant p53 concentration and demonstrate that TP53 hotspot mutations optimally solve an evolutionary trade-off between oncogenic potential and neoantigen immunogenicity. Our model anticipates patient survival in The Cancer Genome Atlas and patients with lung cancer treated with immunotherapy as well as the age of tumour onset in germline carriers of TP53 variants. The predicted differential immunogenicity between hotspot mutations was validated experimentally in patients with cancer and in a unique large dataset of healthy individuals. Our data indicate that immune selective pressure on TP53 mutations has a smaller role in non-cancerous lesions than in tumours, suggesting that targeted immunotherapy may offer an early prophylactic opportunity for the former. Determining the relative contribution of immunogenicity and oncogenic function to the selective advantage of hotspot mutations thus has important implications for both precision immunotherapies and our understanding of tumour evolution.

Spectrum and Excess Risk of Gastrointestinal Tumors in Li-Fraumeni Syndrome.

Li-Fraumeni syndrome (LFS), linked to heterozygous germline pathogenic/likely pathogenic variants in TP53, confers exceptionally high cancer risk, including core cancers (sarcoma, breast, adrenocortical, and brain cancer) among many other cancer types.1 Colorectal cancer (CRC) is most common after the core and hematologic cancers, accounting for ∼2.8% of diagnoses. Stomach and esophageal cancers constitute another 1.3% (TP53 Database; R20, July 2019: https://tp53.isb-cgc.org).2.

Diet and physical activity behaviors: how are they related to illness perceptions, coping, and health-related quality of life in young people with hereditary cancer syndromes?

Individuals with inherited cancer syndromes, such as Li-Fraumeni syndrome (LFS), may be motivated to adopt health-protective behaviors, such as eating more fruits and vegetables and increasing physical activity. Examining these health behaviors among young people with high lifetime genetic cancer risk may provide important insights to guide future behavioral interventions that aim to improve health-related quality of life (HRQOL). We used a self-regulatory framework to investigate relationships among diet and physical activity behaviors and psychosocial constructs (e.g., illness perceptions, coping, HRQOL) in adolescents and young adults (AYAs; aged 15-39 years) with LFS. This longitudinal mixed-methods study included 57 AYAs aged 16-39 years at enrollment), 32 (56%) of whom had a history of one or more cancers. Participants completed one or two telephone interviews and/or an online survey. We thematically analyzed interview data and conducted regression analyses to evaluate relationships among variables. AYAs described adopting healthy diet and physical activity behaviors to assert some control over health and to protect HRQOL. More frequent use of active coping strategies was associated with greater reported daily fruit and vegetable intake. Greater reported physical activity was associated with better quality of psychological health. Healthy diet and physical activity behaviors may function as LFS coping strategies that confer mental health benefits. Clinicians might emphasize these potential benefits and support AYAs in adopting health behaviors that protect multiple domains of health. Future research could use these findings to develop behavioral interventions tailored to AYAs with high genetic cancer risk.

How do young people with a hereditary cancer predisposition syndrome understand and experience cancer survivorship? "With Li-Fraumeni syndrome, it's just an intermission".

OBJECTIVES: Adolescents and young adult (AYA) cancer survivors face unique medical and psychosocial sequalae, including chronic health conditions, late effects of treatment and fear of recurrence. The meaning of cancer survivorship may be further complicated for AYAs with hereditary cancer predisposition syndromes. This study used a patient-centered framework to investigate how AYAs with Li-Fraumeni syndrome (LFS) consider cancer survivorship. METHODS: An interprofessional team conducted 30 semi-structured interviews with AYAs (aged 18-41, mean 31 years) enrolled in the National Cancer Institute's LFS Study (NCT01443468). Twenty had experienced at least one cancer diagnosis. Interview data were thematically analyzed by an inter-professional team using interpretive description and grounded theory methods. FINDINGS: Participants viewed "survivorship" as a period marked by no evidence of formerly diagnosed disease. By contrast, participants felt the label "survivor" was tenuous since LFS is characterized by multiple primary malignancies and uncertainty about intervals between one diagnosis and the next. Many AYAs viewed survivorship as requiring a high degree of suffering. Though many personally rejected "survivor" identities, almost all articulated its various functions including positive, negative, and more complicated connotations. Instead, they chose language to represent a range of beliefs about survival, longevity, prognosis, and activism. CONCLUSIONS: AYAs with LFS struggle with the term "survivor" due to their multi-organ cancer risk, short intervals between malignancies, and evolving identities. Loved ones' cancer-related suffering informed perspectives on survivorship. Survivorship care for AYAs with cancer risk syndromes requires interprofessional interventions that address their unique biomedical and psychosocial needs.

Uptake and timing of bilateral and contralateral risk-reducing mastectomy in women with Li-Fraumeni syndrome.

PURPOSE: Women with Li-Fraumeni Syndrome (LFS) often consider risk-reducing mastectomy (RRM) due to extremely high risk of breast cancer at early ages. Data on uptake of RRM in LFS are scarce, and are inferred from experience in women with pathogenic variants (PVs) in BRCA1/2, despite differences in cancer risks. This study evaluated RRM uptake in a cohort of women with LFS. METHODS: Women (n = 205) with LFS enrolled in NCI's LFS study reported lifetime cancer diagnoses and mastectomies and completed questionnaires regarding reproductive history, cancer worry and risk perceptions. A subset of women participating in an annual cancer screening study received counseling regarding RRM. RESULTS: 65% (n = 71) of women diagnosed with presumed unilateral breast cancer (n = 109) underwent contralateral RRM over their lifetime. Nearly half (49%, n = 25) of the women who did not complete contralateral RRM within one year of their breast cancer diagnosis (n = 51) developed contralateral breast cancer (median interval = 6 years). Only 18.5% (n = 15) of women without breast cancer history (n = 81) underwent bilateral RRM. Median age at bilateral RRM of 39 years was sub-optimal for breast cancer risk reduction. Contralateral RRM was associated with early genetic diagnosis, participation in the screening study, and fewer prior cancers. Bilateral RRM uptake was associated with having had children, having breastfed, and high cancer worry. CONCLUSION: Uptake of contralateral RRM is high in women with LFS. The frequency of contralateral breast cancer necessitates active discussion of benefits of contralateral RRM and counseling regarding bilateral RRM should be tailored to the early age at risk of breast cancer onset in LFS. There is a need for research into the survival and long-term benefits of RRM in LFS.

Cancer incidence, patterns, and genotype-phenotype associations in individuals with pathogenic or likely pathogenic germline TP53 variants: an observational cohort study.

BACKGROUND: Li-Fraumeni syndrome, caused primarily by pathogenic or likely pathogenic germline TP53 variants, is a rare, variably penetrant, cancer predisposition syndrome with very high risks of cancer starting in childhood, including the risk of multiple primary malignancies over an individual's lifespan. We aimed to characterise and quantify cancer incidence, patterns, and genotype-phenotype associations in individuals with pathogenic or likely pathogenic germline TP53 variants. METHODS: This observational cohort study was done in 480 carriers of pathogenic or likely pathogenic germline TP53 variants enrolled in the National Cancer Institute's referral-based longitudinal Li-Fraumeni syndrome study between Aug 1, 2011, and March 24, 2020. Data on personal and family history of cancer were obtained through study questionnaires and validated by medical records. Variants were categorised on the basis of both loss-of-function (LOF) and dominant-negative effect (DNE) properties. Cancer incidence associated with Li-Fraumeni syndrome was compared with that of the general population using the Surveillance, Epidemiology, and End Results (SEER) 1975-2017 registry. Cancer incidence was evaluated with family-clustered Cox regression models and competing risk methods. This study is registered with ClinicalTrials.gov, NCT01443468. FINDINGS: Individuals with Li-Fraumeni syndrome had a nearly 24 times higher incidence of any cancer than the general population (standardised incidence ratio 23·9; 95% CI 21·9-26·0), with the highest comparative incidence from childhood to 30 years of age. The overall cancer incidence remained 10·3 (95% CI 7·9-13·2) times higher than that of the general population after age 50 years. In women, when considering breast cancer as a competing risk, the probability of a first diagnosis of a non-breast cancer malignancy was substantially lower than that of any first cancer (24·4% [95% CI 19·6-30·5] vs 50·4% [43·5-56·5] by age 33·7 years). Overall, DNE_LOF and notDNE_LOF variants were associated with earlier age at first and second cancer compared with notDNE_notLOF and DNE_notLOF variants. The time interval from first to second cancer was shorter among carriers whose first cancer diagnoses were later in life. Multiple cancers were diagnosed within a short timeframe in some individuals, regardless of the order of cancer occurrence. INTERPRETATION: This study adds granularity to the understanding of cancer incidence and patterns in individuals with pathogenic or likely pathogenic germline TP53 variants. Integration of age range-specific cancer incidence estimates, cancer-free survival by functional variant group, the potential impact of risk-reducing mastectomy on female cancer incidence, and data on subsequent malignancies will be important for the development of strategies to optimise cancer screening and management for these individuals. FUNDING: Intramural Research Program, Division of Cancer Epidemiology and Genetics, National Institutes of Health.

Gastrointestinal Hemorrhage: A Manifestation of the Telomere Biology Disorders.

OBJECTIVE: To describe the clinical features, therapeutic interventions, and patient outcomes of gastrointestinal (GI) hemorrhage in individuals with a telomere biology disorder, including dyskeratosis congenita, Hoyeraal-Hreidarsson syndrome, Revesz syndrome, and Coats plus. STUDY DESIGN: Clinical Care Consortium for Telomere Associated Ailments members were invited to contribute data on individuals with telomere biology disorders at their institutions who experienced GI bleeding. Patient demographic, laboratory, imaging, procedural, and treatment information and outcomes were extracted from the medical record. RESULTS: Sixteen patients who experienced GI hemorrhage were identified at 11 centers. Among 14 patients who underwent genetic testing, 8 had mutations in TINF2, 4 had mutations in CTC1 or STN1, and 1 patient each had a mutation in TERC and RTEL1. Ten patients had a history of hematopoietic cell transplantation. The patients with Coats plus and those without Coats plus had similar clinical features and courses. Angiodysplasia of the stomach and/or small bowel was described in 8 of the 12 patients who underwent endoscopy; only 4 had esophageal varices. Various medical interventions were trialed. No single intervention was uniformly associated with cessation of bleeding, although 1 patient had a sustained response to treatment with bevacizumab. Recurrence was common, and the overall long-term outcome for affected patients was poor. CONCLUSIONS: GI bleeding in patients with telomere biology disorders is associated with significant morbidity and with vascular ectasias rather than varices.

Family Identity and Roles in the Context of Li-Fraumeni Syndrome: "No One's Like Us Mutants".

Li-Fraumeni syndrome (LFS) is a rare hereditary cancer syndrome in which individuals have a significantly increased risk of developing multiple cancers throughout the life span. An LFS diagnosis may shift the individual's sense of self and tolerance of cancer risk as they engage in cancer screening and cancer prevention activities. This study examined the impact of family identity on health decision making, communication, and role function. Forty-five families completed one or more interviews during an annual, protocol-specific cancer screening study. An interdisciplinary team analyzed 66 interviews using interpretive description and modified grounding theory. Thematically, identity emerged as an evolving construct regarding self and/or family, embedded in historical and ongoing experiences with LFS. Notions of individual and shared family identities guided decision making related to healthcare and influenced interpersonal communication and role function between supportive networks and families. Alignment between individual, family, and generational identities may shape engagement in genetic testing, risk management, and family life. Medical teams that are unequipped to address the psychosocial challenges that LFS populations face may include mental health professionals on interprofessional care teams to navigate risk management and consequential familial conflict.

Expansion of germline RPS20 mutation phenotype to include Diamond-Blackfan anemia.

Diamond-Blackfan anemia (DBA) is a ribosomopathy of variable expressivity and penetrance characterized by red cell aplasia, congenital anomalies, and predisposition to certain cancers, including early-onset colorectal cancer (CRC). DBA is primarily caused by a dominant mutation of a ribosomal protein (RP) gene, although approximately 20% of patients remain genetically uncharacterized despite exome sequencing and copy number analysis. Although somatic loss-of-function mutations in RP genes have been reported in sporadic cancers, with the exceptions of 5q-myelodysplastic syndrome (RPS14) and microsatellite unstable CRC (RPL22), these cancers are not enriched in DBA. Conversely, pathogenic variants in RPS20 were previously implicated in familial CRC; however, none of the reported individuals had classical DBA features. We describe two unrelated children with DBA lacking variants in known DBA genes who were found by exome sequencing to have de novo novel missense variants in RPS20. The variants affect the same amino acid but result in different substitutions and reduce the RPS20 protein level. Yeast models with mutation of the cognate residue resulted in defects in growth, ribosome biogenesis, and polysome formation. These findings expand the phenotypic spectrum of RPS20 mutation beyond familial CRC to include DBA, which itself is associated with increased risk of CRC.

Suggested application of HER2+ breast tumor phenotype for germline TP53 variant classification within ACMG/AMP guidelines.

Early onset breast cancer is the most common malignancy in women with Li-Fraumeni syndrome, caused by germline TP53 pathogenic variants. It has repeatedly been suggested that breast tumors from TP53 carriers are more likely to be HER2+ than those of noncarriers, but this information has not been incorporated into variant interpretation models for TP53. Breast tumor pathology is already being used quantitatively for assessing pathogenicity of germline variants in other genes, and it has been suggested that this type of evidence can be incorporated into current American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) guidelines for germline variant classification. Here, by reviewing published data and using internal datasets separated by different age groups, we investigated if breast tumor HER2+ status has utility as a predictor of TP53 germline variant pathogenicity, considering age at diagnosis. Overall, our results showed that the identification of HER2+ breast tumors diagnosed before the age of 40 can be conservatively incorporated into the current TP53-specific ACMG/AMP PP4 criterion, following a point system detailed in this manuscript. Further larger studies will be needed to reassess the value of HER2+ breast tumors diagnosed at a later age.

Family Health Leaders: Lessons on Living with Li-Fraumeni Syndrome across Generations.

Li-Fraumeni Syndrome (LFS) is a hereditary disorder that confers an approximately 90% lifetime risk of cancer and requires comprehensive lifetime cancer screening. We explored healthcare roles for managing LFS-related cancer risks and treatments that were assumed by parents, adolescents, and adult children. Semi-structured interviews were conducted with 23 families. Family groupings were comprised of 2-5 members, with the younger generation in each family ranging in age from 7 to 40 years. Using grounded theory methods, we conducted open and focused coding of interview transcript content. Family members described how the role of health leader was implemented in their family, as well as factors such as maturation of a child or death of a member that determined who assumed particular roles and how these roles shifted over time. They often expressed collective responsibility for helping relatives understand LFS and implement appropriate cancer risk management. Members demonstrated their health role by attending others' medical appointments for support or information gathering. The health leader role was intergenerational and provided the family necessary support in navigating complicated healthcare decisions. Our findings provide insight into healthcare providers regarding how LFS patients and their relatives develop unique medical decision-making and caring roles influenced by the hereditary nature of LFS, and how these roles change over time. Providers who are attuned to family role dynamics may be better able to meet relatives' psychosocial and medical needs by understanding how living with LFS influences the family system's functioning and facilitating members' support for each other.

El síndrome de Li-Fraumeni (LFS) es un trastorno hereditario que concede aproximadamente un 90 % de riesgo durante toda la vida de contraer cáncer y exige exámenes completos para la detección del cáncer de por vida. Analizamos los roles sanitarios a la hora de manejar los riesgos y los tratamientos de cáncer relacionados con el LFS que asumieron los padres, los adolescentes y los hijos adultos. Se realizaron entrevistas semiestructuradas con 23 familias. Los agrupamientos familiares estaban compuestos por entre 2 y 5 familiares, donde la edad de la generación más joven de cada familia oscilaba entre 7 y 40 años. Utilizando los métodos de la teoría fundamentada, realizamos una codificación abierta y centrada del contenido de la transcripción de la entrevista. Los miembros de la familia describieron cómo se implementó el rol de jefe de la salud en su familia, así como factores como la maduración de un niño o la muerte de un miembro que determinaron quiénes asumieron roles particulares y cómo estos roles cambiaron con el tiempo. Con frecuencia ellos expresaron la responsabilidad colectiva de ayudar a los familiares a comprender el LFS y a implementar el manejo adecuado del riesgo de contraer cáncer. Los familiares demostraron sus roles sanitarios asistiendo a citas médicas de los demás para recibir apoyo u obtener información. El rol de jefe sanitario fue intergeneracional y proporcionó a la familia el apoyo necesario para manejarse ante decisiones complicadas sobre la asistencia sanitaria. Nuestros resultados brindan información para los prestadores de servicios médicos con respecto a cómo los pacientes de LFS y sus familiares desarrollan roles únicos para la toma de decisiones médicas y el cuidado influenciados por la índole hereditaria del LFS, y cómo estos roles cambian con el tiempo. Es posible que los prestadores que estén acostumbrados a la dinámica de roles familiares sean más capaces de satisfacer las necesidades psicosociales y médicas de los familiares si comprenden cómo vivir con LFS influye en el funcionamiento del sistema familiar y si facilitan el apoyo mutuo de los familiares.

Variable population prevalence estimates of germline TP53 variants: A gnomAD-based analysis.

Reports of variable cancer penetrance in Li-Fraumeni syndrome (LFS) have raised questions regarding the prevalence of pathogenic germline TP53 variants. We previously reported higher-than-expected population prevalence estimates in sequencing databases composed of individuals unselected for cancer history. This study aimed to expand and further evaluate the prevalence of pathogenic and likely pathogenic germline TP53 variants in the gnomAD dataset (version r2.0.2, n = 138,632). Variants were selected and classified based on our previously published algorithm and compared with alternative estimates based on three different classification databases: ClinVar, HGMD, and the UMD_TP53 database. Conservative prevalence estimates of pathogenic and likely pathogenic TP53 variants were within the range of one carrier in 3,555-5,476 individuals. Less stringent classification increased the approximate prevalence to one carrier in every 400-865 individuals, mainly due to the inclusion of the controvertible p.N235S, p.V31I, and p.R290H variants. This study shows a higher-than-expected population prevalence of pathogenic and likely pathogenic germline TP53 variants even with the most conservative estimates. However, these estimates may not necessarily reflect the prevalence of the classical LFS phenotype, which is based upon family history of cancer. Comprehensive approaches are needed to better understand the interplay of germline TP53 variant classification, prevalence estimates, cancer penetrance, and LFS-associated phenotype.

Understanding the evolving phenotype of vascular complications in telomere biology disorders.

Vascular complications such as bleeding due to gastrointestinal telangiectatic anomalies, pulmonary arteriovenous malformations, hepatopulmonary syndrome, and retinal vessel abnormalities are being reported in patients with telomere biology disorders (TBDs) more frequently than previously described. The international clinical care consortium of telomere-associated ailments and family support group Dyskeratosis Congenita Outreach, Inc. held a workshop on vascular abnormalities in the TBDs at the National Cancer Institute in October 2017. Clinicians and basic scientists reviewed current data on vascular complications, hypotheses for the underlying biology and developed new collaborations to address the etiology and clinical management of vascular complications in TBDs.

Couples coping with screening burden and diagnostic uncertainty in Li-Fraumeni syndrome: Connection versus independence.

PURPOSE: Li-Fraumeni Syndrome (LFS) is an inherited tumor predisposition syndrome with lifetime cancer risks approaching 100% and evolving risk-management strategies. This study evaluated couples' coping with LFS-related burdens. RESEARCH APPROACH: Constructivist grounded theory and anticipatory loss frameworks guided design and analysis. SAMPLE AND METHODS: Twenty-six individuals enrolled in the NCI LFS Family Study completed semi-structured interviews with their partner during annual screening visits. An interdisciplinary team completed open and focused coding to identify patterns of coping and adaptation. FINDINGS: Couples described living with ambiguous danger, a state of chronic apprehension resulting from LFS-associated uncertainties. Most couples communicated openly and alternated shouldering the burden, while others engaged in protective buffering to shield each other from distress and sustain the appearance of normalcy. INTERPRETATION: Optimally, coping reduces shared psychosocial distress, yet some strategies may inadvertently increase disconnection. IMPLICATIONS: Mental health support is critical for both partners coping with LFS, together and separately.

Complex phenotype of dyskeratosis congenita and mood dysregulation with novel homozygous RTEL1 and TPH1 variants.

Dyskeratosis congenita (DC) is an inherited bone marrow failure syndrome caused by germline mutations in telomere biology genes. Patients have extremely short telomeres for their age and a complex phenotype including oral leukoplakia, abnormal skin pigmentation, and dysplastic nails in addition to bone marrow failure, pulmonary fibrosis, stenosis of the esophagus, lacrimal ducts and urethra, developmental anomalies, and high risk of cancer. We evaluated a patient with features of DC, mood dysregulation, diabetes, and lack of pubertal development. Family history was not available but genome-wide genotyping was consistent with consanguinity. Whole exome sequencing identified 82 variants of interest in 80 genes based on the following criteria: homozygous, <0.1% minor allele frequency in public and in-house databases, nonsynonymous, and predicted deleterious by multiple in silico prediction programs. Six genes were identified likely contributory to the clinical presentation. The cause of DC is likely due to homozygous splice site variants in regulator of telomere elongation helicase 1, a known DC and telomere biology gene. A homozygous, missense variant in tryptophan hydroxylase 1 may be clinically important as this gene encodes the rate limiting step in serotonin biosynthesis, a biologic pathway connected with mood disorders. Four additional genes (SCN4A, LRP4, GDAP1L1, and SPTBN5) had rare, missense homozygous variants that we speculate may contribute to portions of the clinical phenotype. This case illustrates the value of conducting detailed clinical and genomic evaluations on rare patients in order to identify new areas of research into the functional consequences of rare variants and their contribution to human disease.

Novel and known ribosomal causes of Diamond-Blackfan anaemia identified through comprehensive genomic characterisation.

BACKGROUND: Diamond-Blackfan anaemia (DBA) is an inherited bone marrow failure syndrome (IBMFS) characterised by erythroid hypoplasia. It is associated with congenital anomalies and a high risk of developing specific cancers. DBA is caused predominantly by autosomal dominant pathogenic variants in at least 15 genes affecting ribosomal biogenesis and function. Two X-linked recessive genes have been identified. OBJECTIVES: We aim to identify the genetic aetiology of DBA. METHODS: Of 87 families with DBA enrolled in an institutional review board-approved cohort study (ClinicalTrials.gov Identifier:NCT00027274), 61 had genetic testing information available. Thirty-five families did not have a known genetic cause and thus underwent comprehensive genomic evaluation with whole exome sequencing, deletion and CNV analyses to identify their disease-associated pathogenic variant. Controls for functional studies were healthy mutation-negative individuals enrolled in the same study. RESULTS: Our analyses uncovered heterozygous pathogenic variants in two previously undescribed genes in two families. One family had a non-synonymous variant (p.K77N) in RPL35; the second family had a non-synonymous variant (p. L51S) in RPL18. Both of these variants result in pre-rRNA processing defects. We identified heterozygous pathogenic variants in previously known DBA genes in 16 of 35 families. Seventeen families who underwent genetic analyses are yet to have a genetic cause of disease identified. CONCLUSIONS: Overall, heterozygous pathogenic variants in ribosomal genes were identified in 44 of the 61 families (72%). De novo pathogenic variants were observed in 57% of patients with DBA. Ongoing studies of DBA genomics will be important to understand this complex disorder.

Correlation of Leukocyte Telomere Length Measurement Methods in Patients with Dyskeratosis Congenita and in Their Unaffected Relatives.

Several methods have been employed to measure telomere length (TL) in human studies. It has been difficult to directly compare the results from these studies because of differences in the laboratory techniques and output parameters. We compared TL measurements (TLMs) by the three most commonly used methods, quantitative polymerase chain reaction (qPCR), flow cytometry with fluorescence in situ hybridization (flow FISH) and Southern blot, in a cohort of patients with the telomere biology disorder dyskeratosis congenita (DC) and in their unaffected relatives (controls). We observed a strong correlation between the Southern blot average TL and the flow FISH total lymphocyte TL in both the DC patients and their unaffected relatives (R² of 0.68 and 0.73, respectively). The correlation between the qPCR average TL and that of the Southern blot method was modest (R² of 0.54 in DC patients and of 0.43 in unaffected relatives). Similar results were noted when comparing the qPCR average TL and the flow FISH total lymphocyte TL (R² of 0.49 in DC patients and of 0.42 in unaffected relatives). In conclusion, the strengths of the correlations between the three widely used TL assays (qPCR, flow FISH, and Southern blot) were significantly different. Careful consideration is warranted when selecting the method of TL measurement for research and for clinical studies.

Risks of first and subsequent cancers among TP53 mutation carriers in the National Cancer Institute Li-Fraumeni syndrome cohort.

BACKGROUND: Li-Fraumeni syndrome (LFS) is an autosomal dominant cancer predisposition syndrome characterized by a very high lifetime cancer risk and an early age at diagnosis of a wide cancer spectrum. Precise estimates for the risk of first and subsequent cancers are lacking. METHODS: The National Cancer Institute's Li-Fraumeni Syndrome Study includes families meeting the diagnostic criteria for LFS or Li-Fraumeni-like syndrome, and individuals with a germline TP53 mutation, choroid plexus carcinoma, adrenocortical carcinoma, or ≥3 cancers. Herein, we estimated the cumulative risk and annual hazards for first and second cancers among TP53 mutation carriers (TP53 positive [TP53+]) using MATLAB statistical software. RESULTS: This study evaluated 286 TP53+ individuals from 107 families. The cumulative cancer incidence was 50% by age 31 years among TP53+ females and 46 years among males, and nearly 100% by age 70 years for both sexes. Cancer risk was highest after age 20 years for females, mostly due to breast cancer, whereas among males the risk was higher in childhood and later adulthood. Among females, the cumulative incidence rates by age 70 years for breast cancer, soft tissue sarcoma, brain cancer, and osteosarcoma were 54%, 15%, 6%, and 5%, respectively. Among males, the incidence rates were 22%, 19%, and 11%, respectively, for soft tissue sarcoma, brain cancer, and osteosarcoma. Approximately 49% of those with 1 cancer developed at least another cancer after a median of 10 years. The average age-specific risk of developing a second cancer was comparable to that of developing a first cancer. CONCLUSIONS: The cumulative cancer risk in TP53 + individuals was very high and varied by sex, age, and cancer type. Additional work, including prospective risk estimates, is needed to better inform personalized risk management. Cancer 2016;122:3673-81. © 2016 American Cancer Society.

Investigation of chromosome X inactivation and clinical phenotypes in female carriers of DKC1 mutations.

Dyskeratosis congenita (DC) is an inherited bone marrow failure and cancer susceptibility syndrome caused by germline mutations in telomere biology genes. Germline mutations in DKC1, which encodes the protein dyskerin, cause X-linked recessive DC. Because of skewed X-chromosome inactivation, female DKC1 mutation carriers do not typically develop clinical features of DC. This study evaluated female DKC1 mutation carriers with DC-associated phenotypes to elucidate the molecular features of their mutations, in comparison with unaffected carriers and mutation-negative female controls. All female DKC1 mutation carriers had normal leukocyte subset telomere lengths and similarly skewed X-inactivation in multiple tissue types, regardless of phenotype. We observed dyskerin expression, telomerase RNA accumulation, and pseudouridylation present in all mutation carriers at levels comparable to healthy wild-type controls. Our study suggests that mechanisms in addition to X chromosome inactivation, such as germline mosaicism or epigenetics, may contribute to DC-like phenotypes present in female DKC1 mutation carriers. Future studies are warranted to understand the molecular mechanisms associated with the phenotypic variability in female DKC1 mutation carriers, and to identify those at risk of disease. Am. J. Hematol. 91:1215-1220, 2016. © 2016 Wiley Periodicals, Inc.