Most Fanconi anemia heterozygotes are not at increased cancer risk: A genome-first DiscovEHR cohort population study.

PURPOSE: Fanconi anemia (FA) is a bone marrow failure and cancer predisposition syndrome caused primarily by biallelic pathogenic variants in 1 of 22 genes involved in DNA interstrand cross-link repair. An enduring question concerns cancer risk of those with a single pathogenic FA gene variant. To investigate all FA genes, this study utilized the DiscovEHR cohort of 170,503 individuals with exome sequencing and electronic health data. METHODS: 5822 subjects with a single pathogenic variant in an FA gene were identified. Two control groups were used in primary analysis deriving cancer risk signals. Secondary exploratory analysis was conducted using the UK Biobank and The Cancer Genome Atlas. RESULTS: Signals for elevated cancer risk were found in all 5 known cancer predisposition genes. Among the remaining 15 genes associated with autosomal recessive inheritance cancer risk signals were found for 4 cancers across 3 genes in the primary cohort but were not validated in secondary cohorts. CONCLUSION: To our knowledge, this is the first and largest FA heterozygote study to use genomic ascertainment and validates well-established cancer predispositions in 5 genes, whereas finding insufficient evidence of predisposition in 15 others. Our findings inform clinical surveillance given how common pathogenic FA variants are in the population.

Genome-first approach of the prevalence and cancer phenotypes of pathogenic or likely pathogenic germline TP53 variants.

Pathogenic or likely pathogenic (P/LP) germline TP53 variants are the primary cause of Li-Fraumeni syndrome (LFS), a hereditary cancer predisposition disorder characterized by early-onset cancers. The population prevalence of P/LP germline TP53 variants is estimated to be approximately one in every 3,500 to 20,000 individuals. However, these estimates are likely impacted by ascertainment biases and lack of clinical and genetic data to account for potential confounding factors, such as clonal hematopoiesis. Genome-first approaches of cohorts linked to phenotype data can further refine these estimates by identifying individuals with variants of interest and then assessing their phenotypes. This study evaluated P/LP germline (variant allele fraction ≥30%) TP53 variants in three cohorts: UK Biobank (UKB, n = 200,590), Geisinger (n = 170,503), and Penn Medicine Biobank (PMBB, n = 43,731). A total of 109 individuals were identified with P/LP germline TP53 variants across the three databases. The TP53 p.R181H variant was the most frequently identified (9 of 109 individuals, 8%). A total of 110 cancers, including 47 hematologic cancers (47 of 110, 43%), were reported in 71 individuals. The prevalence of P/LP germline TP53 variants was conservatively estimated as 1:10,439 in UKB, 1:3,790 in Geisinger, and 1:2,983 in PMBB. These estimates were calculated after excluding related individuals and accounting for the potential impact of clonal hematopoiesis by excluding heterozygotes who ever developed a hematologic cancer. These varying estimates likely reflect intrinsic selection biases of each database, such as healthcare or population-based contexts. Prospective studies of diverse, young cohorts are required to better understand the population prevalence of germline TP53 variants and their associated cancer penetrance.

Development of a Polygenic Risk Score to Predict Diverticulitis.

BACKGROUND: Despite its prevalence and associated morbidity, we remain limited in our ability to predict the course of a patient with diverticular disease. Although several clinical and genetic risk factors have been identified, we do not know how these factors relate to one another. OBJECTIVE: Our aim was to determine whether a polygenic risk score could improve risk prediction for diverticulitis and recurrent diverticulitis compared with a model using only clinical factors. DESIGN: This is an observational study. SETTING: The study examines the predictive ability of a polygenic risk score for diverticulitis developed using prior genome-wide association studies and validated using the MyCode biobank. PATIENTS: This study included patients of European ancestry in the Geisinger Health System who were enrolled in the MyCode Community Health biobanking program. MAIN OUTCOME MEASURES: The ability of a polygenic risk score to predict diverticulosis, diverticulitis, and recurrent diverticulitis was the main outcome measure of this study. RESULTS: A total of 60,861 patients were included, of whom 9912 (16.3%) had diverticulosis or diverticulitis (5015 with diverticulosis and 4897 with diverticulitis). When divided into deciles, our polygenic risk score stratified patients by risk of both diverticulosis and diverticulitis with a 2-fold difference in disease risk between the highest and lowest deciles for diverticulitis and a 4.8-fold difference for recurrent complicated diverticulitis. When compared with clinical factors alone, our polygenic risk score was able to improve risk prediction of recurrent diverticulitis. LIMITATIONS: Our population is largely located in a single geographic region and were classified by disease status, using international classification of diseases codes. CONCLUSIONS: This predictive model stratifies patients based on genetic risk for diverticular disease. The increased frequency of recurrent disease in our high-risk patients suggests that a polygenic risk score, in addition to other factors, may help guide the discussion regarding surgical intervention. See Video Abstract . DESARROLLO DE UNA PUNTUACIN DE RIESGO POLIGNICO PARA PREDECIR LA DIVERTICULITIS: ANTECEDENTES:A pesar de su prevalencia y morbilidad asociada, nuestra capacidad para predecir el curso en un paciente con enfermedad diverticular sigue siendo limitada. Si bien se han identificado varios factores de riesgo clínicos y genéticos, no sabemos cómo se relacionan estos factores entre sí.OBJETIVO:Determinar si una puntuación de riesgo poligénico podría mejorar la predicción del riesgo de diverticulitis y diverticulitis recurrente en comparación con un modelo que utiliza solo factores clínicos.DISEÑO:Un estudio observacional que examina la capacidad predictiva de una puntuación de riesgo poligénico para la diverticulitis desarrollada usando estudios previos de asociación amplia del genoma y validada usando el biobanco MyCode.ÁMBITOS Y PACIENTES:Pacientes de ascendencia europea en el Sistema de Salud Geisinger que estaban inscritos en el programa de biobancos MyCode Community Health.PRINCIPALES MEDIDAS DE VALORACIÓN:La capacidad de una puntuación de riesgo poligénico para predecir diverticulosis, diverticulitis y diverticulitis recurrente.RESULTADOS:Se incluyeron un total de 60.861 pacientes, de los cuales 9.912 (16,3%) presentaban diverticulosis o diverticulitis (5.015 con diverticulosis y 4.897 con diverticulitis). Cuando se dividió en deciles, nuestra puntuación de riesgo poligénico estratificó a los pacientes según el riesgo de diverticulosis y diverticulitis con una diferencia de 2 veces en el riesgo de enfermedad entre los deciles más alto y más bajo para diverticulitis y una diferencia de 4,8 veces para diverticulitis complicada recurrente. En comparación con los factores clínicos solos, nuestra puntuación de riesgo poligénico pudo mejorar la predicción del riesgo de diverticulitis recurrente.LIMITACIONES:Nuestra población se encuentra en gran parte en una sola región geográfica y se clasificó por estado de enfermedad utilizando códigos de clasificación internacional de enfermedades.CONCLUSIONES:Este modelo predictivo estratifica a los pacientes en función del riesgo genético de enfermedad diverticular. La mayor frecuencia de enfermedad recurrente en nuestros pacientes de alto riesgo sugiere que un puntaje de riesgo poligénico, además de otros factores, puede ayudar a guiar la discusión sobre la intervención quirúrgica. (Traducción- Dr. Ingrid Melo ).

Intronic Germline DICER1 Variants in Patients With Sertoli-Leydig Cell Tumor.

Germline pathogenic loss-of-function (pLOF) variants in DICER1 are associated with a predisposition for a variety of solid neoplasms, including pleuropulmonary blastoma and Sertoli-Leydig cell tumor (SLCT). The most common DICER1 pLOF variants include small insertions or deletions leading to frameshifts, and base substitutions leading to nonsense codons or altered splice sites. Larger deletions and pathogenic missense variants occur less frequently. Identifying these variants can trigger surveillance algorithms with potential for early detection of DICER1-related cancers and cascade testing of family members. However, some patients with DICER1-associated tumors have no pLOF variants detected by germline or tumor testing. Here, we present two patients with SLCT whose tumor sequencing showed only a somatic missense DICER1 RNase IIIb variant. Conventional exon-directed germline sequencing revealed no pLOF variants. Using a custom capture panel, we discovered novel intronic variants, ENST00000343455.7: c.1752+213A>G and c.1509+16A>G, that appear to interfere with normal splicing. We suggest that when no DICER1 pLOF variants or large deletions are discovered in exonic regions despite strong clinical suspicion, intron sequencing and splicing analysis should be performed.

Estimated Prevalence, Tumor Spectrum, and Neurofibromatosis Type 1-Like Phenotype of CDKN2A-Related Melanoma-Astrocytoma Syndrome.

Importance: Knowledge about the prevalence and tumor types of CDKN2A-related melanoma-astrocytoma syndrome (MAS) is limited and could improve disease recognition. Objective: To estimate the prevalence and describe the tumor types of MAS. Design, Setting, and Participants: This retrospective cohort study analyzed all available MAS cases from medical centers in the US (2 sites) and Europe (2 sites) and from biomedical population genomic databases (UK Biobank [United Kingdom], Geisinger MyCode [US]) between January 1, 1976, and December 31, 2020. Patients with MAS with CDKN2A germline pathogenic variants and 1 or more neural tumors were included. Data were analyzed from June 1, 2022, to January 31, 2023. Main Outcomes and Measures: Disease prevalence and tumor frequency. Results: Prevalence of MAS ranged from 1 in 170 503 (n = 1 case; 95% CI, 1:30 098-1:965 887) in Geisinger MyCode (n = 170 503; mean [SD] age, 58.9 [19.1] years; 60.6% women; 96.2% White) to 1 in 39 149 (n = 12 cases; 95% CI, 1:22 396-1:68 434) in UK Biobank (n = 469 789; mean [SD] age, 70.0 [8.0] years; 54.2% women; 94.8% White). Among UK Biobank patients with MAS (n = 12) identified using an unbiased genomic ascertainment approach, brain neoplasms (4 of 12, 33%; 1 glioblastoma, 1 gliosarcoma, 1 astrocytoma, 1 unspecified type) and schwannomas (3 of 12, 25%) were the most common malignant and benign neural tumors, while cutaneous melanoma (2 of 12, 17%) and head and neck squamous cell carcinoma (2 of 12, 17%) were the most common nonneural malignant neoplasms. In a separate case series of 14 patients with MAS from the US and Europe, brain neoplasms (4 of 14, 29%; 2 glioblastomas, 2 unspecified type) and malignant peripheral nerve sheath tumor (2 of 14, 14%) were the most common neural cancers, while cutaneous melanoma (4 of 14, 29%) and sarcomas (2 of 14, 14%; 1 liposarcoma, 1 unspecified type) were the most common nonneural cancers. Cutaneous neurofibromas (7 of 14, 50%) and schwannomas (2 of 14, 14%) were also common. In 1 US family, a father and son with MAS had clinical diagnoses of neurofibromatosis type 1 (NF1). Genetic testing of the son detected a pathogenic CDKN2A splicing variant (c.151-1G>C) and was negative for NF1 genetic alterations. In UK Biobank, 2 in 150 (1.3%) individuals with clinical NF1 diagnoses had likely pathogenic variants in CDKN2A, including 1 individual with no detected variants in the NF1 gene. Conclusions and Relevance: This cohort study estimates the prevalence and describes the tumors of MAS. Additional studies are needed in genetically diverse populations to further define population prevalence and disease phenotypes.

Estimated Prevalence and Clinical Manifestations of UBA1 Variants Associated With VEXAS Syndrome in a Clinical Population.

Importance: VEXAS (vacuoles, E1-ubiquitin-activating enzyme, X-linked, autoinflammatory, somatic) syndrome is a disease with rheumatologic and hematologic features caused by somatic variants in UBA1. Pathogenic variants are associated with a broad spectrum of clinical manifestations. Knowledge of prevalence, penetrance, and clinical characteristics of this disease have been limited by ascertainment biases based on known phenotypes. Objective: To determine the prevalence of pathogenic variants in UBA1 and associated clinical manifestations in an unselected population using a genomic ascertainment approach. Design, Setting, and Participants: This retrospective observational study evaluated UBA1 variants in exome data from 163 096 participants within the Geisinger MyCode Community Health Initiative. Clinical phenotypes were determined from Geisinger electronic health record data from January 1, 1996, to January 1, 2022. Exposures: Exome sequencing was performed. Main Outcomes and Measures: Outcome measures included prevalence of somatic UBA1 variation; presence of rheumatologic, hematologic, pulmonary, dermatologic, and other findings in individuals with somatic UBA1 variation on review of the electronic health record; review of laboratory data; bone marrow biopsy pathology analysis; and in vitro enzymatic assays. Results: In 163 096 participants (mean age, 52.8 years; 94% White; 61% women), 11 individuals harbored likely somatic variants at known pathogenic UBA1 positions, with 11 of 11 (100%) having clinical manifestations consistent with VEXAS syndrome (9 male, 2 female). A total of 5 of 11 individuals (45%) did not meet criteria for rheumatologic and/or hematologic diagnoses previously associated with VEXAS syndrome; however, all individuals had anemia (hemoglobin: mean, 7.8 g/dL; median, 7.5 g/dL), which was mostly macrocytic (10/11 [91%]) with concomitant thrombocytopenia (10/11 [91%]). Among the 11 patients identified, there was a pathogenic variant in 1 male participant prior to onset of VEXAS-related signs or symptoms and 2 female participants had disease with heterozygous variants. A previously unreported UBA1 variant (c.1861A>T; p.Ser621Cys) was found in a symptomatic patient, with in vitro data supporting a catalytic defect and pathogenicity. Together, disease-causing UBA1 variants were found in 1 in 13 591 unrelated individuals (95% CI, 1:7775-1:23 758), 1 in 4269 men older than 50 years (95% CI, 1:2319-1:7859), and 1 in 26 238 women older than 50 years (95% CI, 1:7196-1:147 669). Conclusions and Relevance: This study provides an estimate of the prevalence and a description of the clinical manifestations of UBA1 variants associated with VEXAS syndrome within a single regional health system in the US. Additional studies are needed in unselected and genetically diverse populations to better define general population prevalence and phenotypic spectrum.

A Genome-First Approach to Estimate Prevalence of Germline Pathogenic Variants and Risk of Pancreatic Cancer in Select Cancer Susceptibility Genes.

Patients with germline pathogenic variants (GPV) in cancer predisposition genes are at increased risk of pancreatic ductal adenocarcinoma (PDAC), the most common type of pancreatic cancer. The genes most frequently found to harbor GPV in unselected PDAC cases are ATM, BRCA1, BRCA2, CDKN2A, CHEK2, and PALB2. However, GPV prevalence and gene-specific associations have not been extensively studied in the general population. To further explore these associations, we analyzed genomic and phenotypic data obtained from the UK Biobank (UKB) and Geisinger MyCode Community Health Initiative (GHS) cohorts comprising 200,600 and 175,449 participants, respectively. We estimated the frequency and calculated relative risks (RRs) of heterozygotes in both cohorts and a subset of individuals with PDAC. The combined frequency of heterozygous carriers of GPV in the general population ranged from 1.22% for CHEK2 to 0.05% for CDKN2A. The frequency of GPV in PDAC cases varied from 2.38% (ATM) to 0.19% (BRCA1 and CDKN2A). The RRs of PDAC were elevated for all genes except for BRCA1 and varied widely by gene from high (ATM) to low (CHEK2, BRCA2). This work expands our understanding of the frequencies of GPV heterozygous carriers and associations between PDAC and GPV in several important PDAC susceptibility genes.

Association of varicose veins with rare protein-truncating variants in PIEZO1 identified by exome sequencing of a large clinical population.

OBJECTIVE: The present study sought to determine whether protein-truncating variants (PTVs) in PIEZO1 and CASZ1 genes, previously shown to be associated with varicose veins, were associated with an altered risk of varicose veins. METHODS: An exome sequence database of 131,918 participants from the Geisinger MyCode Community Health Initiative was used to identify individuals with genetic variants in the PIEZO1 or CASZ1 gene. Clinical phenotypes, including varicose vein diagnoses, were determined by analysis of the electronic health record data. RESULTS: We identified 12,531 individuals (9.5%) with a diagnosis of varicose veins. Exome sequence data identified 92 PIEZO1 PTVs in 305 heterozygous carriers. PIEZO1 PTVs were significantly enriched in those with varicose vein (0.37% of cases vs 0.22% of controls; odds ratio [OR], 1.7; P = .0010). Nearly all varicose vein cases were associated with frameshift or stop-gain PTVs (OR, 3.0 for stop-gain [P = .0001]; OR, 2.9 for frameshift variants [P < .0001]). In the varicose vein cases, the PTV carriers were more likely to have an encounter with a vascular surgeon (62.5% for PTV carriers; 36.9% for noncarriers; P = .0003) and more likely to have received vein ablation therapy (OR, 6.9; P < .0001). No association was found between PIEZO1 PTVs and lymphedema, and no association was found for rare missense variants in PIEZO1 with varicose veins. PTVs in CASZ1 were extremely rare (16 total carriers), with none identified in those with varicose vein. CONCLUSIONS: Rare PTVs in PIEZO1 but not CASZ1 were associated with varicose veins and the need for vein ablation therapy. These results have demonstrated that PTVs in the PIEZO1 gene are rare but represent strong genetic risk factors for varicose veins and the need for vein ablation therapy. These results have also identified a potential biologic mechanism and target for the development of novel therapies.

A Genome-First Approach to Characterize DICER1 Pathogenic Variant Prevalence, Penetrance, and Phenotype.

Importance: Genetic disorders are historically defined through phenotype-first approaches. However, risk estimates derived from phenotype-linked ascertainment may overestimate severity and penetrance. Pathogenic variants in DICER1 are associated with increased risks of rare and common neoplasms and thyroid disease in adults and children. This study explored how effectively a genome-first approach could characterize the clinical traits associated with germline DICER1 putative loss-of-function (pLOF) variants in an unselected clinical cohort. Objective: To examine the prevalence, penetrance, and phenotypic characteristics of carriers of germline DICER1 pLOF variants via genome-first ascertainment. Design, Setting, and Participants: This cohort study classifies DICER1 variants in germline exome sequence data from 92 296 participants of the Geisinger MyCode Community Health Initiative. Data for each MyCode participant were used from the start of the Geisinger electronic health record to February 1, 2018. Main Outcomes and Measures: Prevalence of germline DICER1 variation; penetrance of malignant tumors and thyroid disease in carriers of germline DICER1 variation; structured, manual review of electronic health records; and DICER1 sequencing of available tumors from an associated cancer registry. Results: A total of 92 296 adults (mean [SD] age, 59 [18] years; 98% white; 60% female) participated in the study. Germline DICER1 pLOF variants were observed in 1 in 3700 to 1 in 4600 participants, more than double the expected prevalence. Malignant tumors (primarily thyroid carcinoma) were observed in 4 of 25 participants (16%) with DICER1 pLOF variants, which is comparable (by 50 years of age) to the frequency of neoplasms in the largest registry- and clinic-based (phenotype-first) DICER1 studies published to date. DICER1 pLOF variants were significantly associated with risks of thyroidectomy (odds ratio [OR], 6.0; 95% CI, 2.2-16.3; P = .007) and thyroid cancer (OR, 9.2; 95% CI, 2.1-34.7; P = .02) compared with controls, but there was not a significant increase in the risk of goiter (OR, 1.8; 95% CI, 0.7-4.9). A female patient in her 80s who was a carrier of a germline DICER1 hotspot variant was apparently healthy on electronic health record review. The term DICER1 did not appear in any of the medical records of the 25 participants with a pLOF DICER1 variant, even in those affected with a known DICER1-associated tumor or thyroid phenotype. Conclusions and Relevance: This cohort study was able to ascertain individuals with germline DICER1 variants based on a genome-first approach rather than through a previously established DICER1-related phenotype. Use of the genome-first approach may complement more traditional approaches to syndrome delineation and may be an efficient approach for risk estimation.

Dose-dependent effect of aerobic exercise on inflammatory biomarkers in a randomized controlled trial of women at high risk of breast cancer.

BACKGROUND: Increased levels of inflammation are associated with many diseases, including cancer. Physical activity can lower breast cancer risk as well as levels of inflammation. The Women In Steady Exercise Research (WISER) Sister trial was a randomized controlled trial that investigated the effects of a dosed, moderate to vigorous, aerobic exercise intervention on levels of inflammation in premenopausal women who were at high risk of developing breast cancer. METHODS: Participants were randomized to control (<75 minutes per week; 41 patients), low-dose exercise (150 minutes per week; 38 patients), or high-dose exercise (300 minutes per week; 37 patients) groups. The 5-menstrual cycles-long, home-based treadmill exercise intervention gradually increased in minutes per week and intensity up to a maximum of 80% of the age-predicted maximum heart rate. Blood was collected at baseline and at follow-up and assayed for chemokine (C-C motif) ligand 2 (CCL2), interleukin 10 (IL-10), interleukin 12 (IL-12), and tumor necrosis factor α (TNF-α). RESULTS: A linear dose-response relationship was observed for the proinflammatory biomarkers CCL2 (%Δ of -5.44% in the control group, -0.03% in the low-dose exercise group, and 1.54% in the high-dose exercise group), IL-12 (%Δ of -21.5% in the control group, 38.2% in the low-dose exercise group, and 25.8% in the high-dose exercise group,) and TNF-α (%Δ of -4.69% in the control group, 9.51% in the low-dose exercise group, and 15.7% in the high-dose exercise group) but not for the anti-inflammatory biomarker IL-10 (%Δ of 5.05% in the control group, 6.05% in the low-dose exercise group, and 10.6% in the high-dose exercise group). For IL-12 and TNF-α, the percentage change was significantly higher in the low-dose (IL-12: P < .001; and TNF-α: P = .01) and high-dose (IL-12: P < .001; and TNF-α: P < .001) exercise groups compared with the control group. CONCLUSIONS: Moderate to vigorous aerobic exercise appeared to increase levels of proinflammatory biomarkers in a dose-dependent manner in a population of healthy women at high risk of developing breast cancer. The results of the current study suggest that for healthy premenopausal women, the mechanism of reduced breast cancer risk observed in physically active individuals may not be a result of reduced levels of inflammation.

Schweinfurthin natural products induce regression of murine melanoma and pair with anti-PD-1 therapy to facilitate durable tumor immunity.

Metastatic melanoma is a significant clinical problem with a 5-year survival rate of only 15-20%. Recent approval of new immunotherapies and targeted inhibitors have provided much needed options for these patients, in some cases promoting dramatic disease regressions. In particular, antibody-based therapies that block the PD-1/PD-L1 checkpoint inhibitory pathway have achieved an increased overall response rate in metastatic melanoma, yet durable response rates are reported only around 15%. To improve the overall and durable response rates for advanced-stage melanoma, combined targeted and immune-based therapies are under investigation. Here, we investigated how the natural products called schweinfurthins, which have selective anti-proliferative activity against many cancer types, impact anti-(α)PD-1-mediated immunotherapy of murine melanomas. Two different compounds efficiently reduced the growth of human and murine melanoma cells in vitro and induced plasma membrane surface localization of the ER-resident protein calreticulin in B16.F10 melanoma cells, an indicator of immunogenic cell death. In addition, both compounds improved αPD-1-mediated immunotherapy of established tumors in immunocompetent C57BL/6 mice either by delaying tumor progression or resulting in complete tumor regression. Improved immunotherapy was accomplished following only a 5-day course of schweinfurthin, which was associated with initial tumor regression even in the absence of αPD-1. Schweinfurthin-induced tumor regression required an intact immune system as tumors were unaffected in NOD scid gamma (NSG) mice. These results indicate that schweinfurthins improve αPD-1 therapy, leading to enhanced and durable anti-tumor immunity and support the translation of this novel approach to further improve response rates for metastatic melanoma.

Durable complete responses off all treatment in patients with metastatic malignant melanoma after sequential immunotherapy followed by a finite course of BRAF inhibitor therapy.

We report 3 cases of durable complete response (CR) in patients with BRAF-mutated metastatic melanoma who were initially treated unsuccessfully with sequential immunotherapies (high dose interleukin 2 followed by ipilimumab with or without concurrent radiation therapy). After progression during or post immunotherapy, these patients were given BRAF inhibitor therapy and developed rapid CRs. Based on the concomitant presence of autoimmune manifestations (including vitiligo and hypophysitis), we postulated that there was a synergistic effect between the prior immune therapy and the BRAF targeting agents. Accordingly, the inhibitors were gradually weaned off beginning at 3 months and were stopped completely at 9-12 months. The three patients remain well and in CR off of all therapy at up to 15 months radiographic follow-up. The institution of the BRAF therapy was associated with development of severe rheumatoid-like arthritis in 2 patients which persisted for months after discontinuation of therapy, suggesting it was not merely a known toxicity of BRAF inhibitors (arthralgias). On immunologic analysis, these patients had high levels of non-T-regulatory, CD4 positive effector phenotype T-cells, which persisted after completion of therapy. Of note, we had previously reported a similar phenomenon in patients with metastatic melanoma who failed high dose interleukin-2 and were then placed on a finite course of temozolomide with rapid complete responses that have remained durable for many years after discontinuation of temozolomide. We postulate that a finite course of cytotoxic or targeted therapy specific for melanoma given after apparent failure of prior immunotherapy can result in complete and durable remissions that may persist long after the specific cytotoxic or targeted agents have been discontinued suggesting the existence of sequence specific synergism between immunotherapy and these agents. Here, we discuss these cases in the context of the literature on synergy between conventional or targeted cytotoxic therapy and immunotherapy in cancer treatment.

Randomized controlled trial of oral glutathione supplementation on body stores of glutathione.

PURPOSE: Glutathione (GSH), the most abundant endogenous antioxidant, is a critical regulator of oxidative stress and immune function. While oral GSH has been shown to be bioavailable in laboratory animal models, its efficacy in humans has not been established. Our objective was to determine the long-term effectiveness of oral GSH supplementation on body stores of GSH in healthy adults. METHODS: A 6-month randomized, double-blinded, placebo-controlled trial of oral GSH (250 or 1,000 mg/day) on GSH levels in blood, erythrocytes, plasma, lymphocytes and exfoliated buccal mucosal cells was conducted in 54 non-smoking adults. Secondary outcomes on a subset of subjects included a battery of immune markers. RESULTS: GSH levels in blood increased after 1, 3 and 6 months versus baseline at both doses. At 6 months, mean GSH levels increased 30-35 % in erythrocytes, plasma and lymphocytes and 260 % in buccal cells in the high-dose group (P < 0.05). GSH levels increased 17 and 29 % in blood and erythrocytes, respectively, in the low-dose group (P < 0.05). In most cases, the increases were dose and time dependent, and levels returned to baseline after a 1-month washout period. A reduction in oxidative stress in both GSH dose groups was indicated by decreases in the oxidized to reduced glutathione ratio in whole blood after 6 months. Natural killer cytotoxicity increased >twofold in the high-dose group versus placebo (P < 0.05) at 3 months. CONCLUSIONS: These findings show, for the first time, that daily consumption of GSH supplements was effective at increasing body compartment stores of GSH.

Why Do CD8+ T Cells become Indifferent to Tumors: A Dynamic Modeling Approach.

CD8+ T cells have the potential to influence the outcome of cancer pathogenesis, including complete tumor eradication or selection of malignant tumor escape variants. The Simian virus 40 large T-antigen (Tag) oncoprotein promotes tumor formation in Tag-transgenic mice and also provides multiple target determinants (sites) for responding CD8+ T cells in C57BL/6 (H-2(b)) mice. To understand the in vivo quantitative dynamics of CD8+ T cells after encountering Tag, we constructed a dynamic model from in vivo-generated data to simulate the interactions between Tag-expressing cells and CD8+ T cells in distinct scenarios including immunization of wild-type C57BL/6 mice and of Tag-transgenic mice that develop various tumors. In these scenarios the model successfully reproduces the dynamics of both the Tag-expressing cells and antigen-specific CD8+ T cell responses. The model predicts that the tolerance of the site-specific T cells is dependent on their apoptosis rates and that the net growth of CD8+ T cells is altered in transgenic mice. We experimentally validate both predictions. Our results indicate that site-specific CD8+ T cells have tissue-specific apoptosis rates affecting their tolerance to the tumor antigen. Moreover, the model highlights differences in apoptosis rates that contribute to compromised CD8+ T cell responses and tumor progression, knowledge of which is essential for development of cancer immunotherapy.