Signal transducer and activator of transcription 4 is required for the transcription factor T-bet to promote T helper 1 cell-fate determination.

Transcriptional regulatory networks direct the development of specialized cell types. The transcription factors signal tranducer and activator of transcription 4 (Stat4) and T-bet are required for the interleukin-12 (IL-12)-stimulated development of T helper 1 (Th1) cells, although the hierarchy of activity by these factors has not been clearly defined. In this report, we show that these factors did not function in a linear pathway and that each factor played a unique role in programming chromatin architecture for Th1 gene expression, with subsets of genes depending on Stat4, T-bet, or both for expression in Th1 cells. T-bet was not able to transactivate expression of Stat4-dependent genes in the absence of endogenous Stat4 expression. Thus, T-bet requires Stat4 to achieve complete IL-12-dependent Th1 cell-fate determination. These data provide a basis for understanding how transiently activated and lineage-specific transcription factors cooperate in promoting cellular differentiation.

Hypofractionated re-irradiation to the brainstem in children with recurrent brain tumors.

To characterize radiation necrosis following hypofractionated brainstem re-irradiation in pediatric patients, we reviewed 23 cases with 28 tumors invading or abutting brainstem and treated with hypofractionated re-irradiation from 2004 to 2014. Re-irradiation delivered total doses of 16-30 Gy in two to five fractions. The most commons regimens used were 24 Gy in three fractions and 25 Gy in five fractions. At median follow-up of 12.8 months, median overall survival was 14.7 months and eight in-field recurrences were detected (median time 10.5 months). Five patients experienced symptomatic brainstem necrosis, and all having received 24 Gy in three fractions. Hypofractionated brainstem re-irradiation may be safer in five fractions.

Survival Outcomes of Dose-Escalated External Beam Radiotherapy versus Combined Brachytherapy for Intermediate and High Risk Prostate Cancer Using the National Cancer Data Base.

PURPOSE: We evaluated survival outcomes between dose-escalated EBRT (external beam radiotherapy) vs EBRT plus brachytherapy for intermediate and high risk prostate cancer using NCDB (National Cancer Data Base). MATERIALS AND METHODS: Patients with cN0M0 prostate cancer treated from 2004 to 2006 were divided into radiotherapy comparison groups, including EBRT alone (75.6 to 81 Gy) and EBRT (40 to 50.4 Gy) plus brachytherapy with EBRT delivered at 1.8 to 2.0 Gy per fraction. Brachytherapy data were limited to yes/no with no information on modality, dose or schedule. Eligible patients were known to have received androgen deprivation therapy. Overall survival was evaluated using multivariate Cox regression and propensity score matched analyses. RESULTS: Of the 20,279 study patients with prostate cancer, including 12,617 at intermediate risk and 7,662 at high risk, 71.3% received EBRT alone and 28.7% received EBRT plus brachytherapy. Median followup was 82 months (range 3 to 120) and median age was 70 years (range 36 to 90). On multivariate analysis compared to EBRT alone (75.6 to 81 Gy) EBRT plus brachytherapy was associated with improved survival (HR 0.75, p <0.001). This significance remained consistent for intermediate and high risk when analyzed separately (HR 0.73 and 0.76, respectively, each p <0.001). However on subset analysis compared to very high dose EBRT alone (79.2 to 81 Gy) in all patients combined EBRT plus brachytherapy was not associated with improved survival (HR 0.91, p = 0.083). CONCLUSION: Compared to EBRT (75.6 to 81 Gy) we observed an association of EBRT plus brachytherapy with a decreased risk of death in men with intermediate and high risk prostate cancer. However this association was no longer significant when EBRT doses of 79.2 to 81 Gy were used.

Thymic selection pathway regulates the effector function of CD4 T cells.

Recently, a new developmental pathway for CD4 T cells that is mediated by major histocompatibility complex class II-positive thymocytes was identified (Choi, E.Y., K.C. Jung, H.J. Park, D.H. Chung, J.S. Song, S.D. Yang, E. Simpson, and S.H. Park. 2005. Immunity. 23:387-396; Li, W., M.G. Kim, T.S. Gourley, B.P. McCarthy, D.B. Sant'angelo, and C.H. Chang. 2005. Immunity. 23:375-386). We demonstrate that thymocyte-selected CD4 (T-CD4) T cells can rapidly produce interferon gamma and interleukin (IL) 4 upon in vivo and in vitro T cell receptor stimulation. These T-CD4 T cells appear to be effector cells producing both T helper type 1 (Th1) and Th2 cytokines, and they maintain a potential to produce Th2 cytokines under Th1-skewing conditions in a signal transducer and activator of transcription 6-independent manner. The IL-4 mRNA level is high in CD4 single-positive thymocytes if they are selected on thymocytes, which is at least partly caused by enhanced histone acetylation of the IL-4 locus. However, mice that can generate T-CD4 T cells showed attenuated immune responses in an allergen-induced airway inflammation model, suggesting a protective role for T-CD4 T cells during an airway challenge. Our results imply that this thymic selection pathway plays an important role in determining the effector function of the resulting CD4 cells and in regulating immune response.

STAT3-dependent IL-21 production from T helper cells regulates hematopoietic progenitor cell homeostasis.

The contribution of specific cell types to the production of cytokines that regulate hematopoiesis is still not well defined. We have previously identified T cell-dependent regulation of hematopoietic progenitor cell (HPC) numbers and cycling. In this report, we demonstrated that HPC activity is decreased in mice with STAT3-deficient T cells, a phenotype that is not because of decreased expression of IL-17 or RORγt. STAT3 expression in T cells was required for IL-21 production by multiple T helper subsets, and neutralization of IL-21 resulted in decreased HPC activity identical to that in mice with STAT3-deficient T cells. Importantly, injection of IL-21 rescued HPC activity in mice with STAT3-deficient T cells. Thus, STAT3-dependent IL-21 production in T cells is required for HPC homeostasis.

Tc17 cells are capable of mediating immunity to vaccinia virus by acquisition of a cytotoxic phenotype.

CD8 T cells can acquire cytokine-secreting phenotypes paralleling cytokine production from Th cells. IL-17-secreting CD8 T cells, termed Tc17 cells, were shown to promote inflammation and mediate immunity to influenza. However, most reports observed a lack of cytotoxic activity by Tc17 cells. In this study, we explored the anti-viral activity of Tc17 cells using a vaccinia virus (VV) infection model. Tc17 cells expanded during VV infection, and TCR transgenic Tc17 cells were capable of clearing recombinant VV infection. In vivo, adoptively transferred Tc17 cells lost the IL-17-secreting phenotype, even in the absence of stimulation, but they did not acquire IFN-gamma-secreting potential unless stimulated with a virus-encoded Ag. However, examination of cells following infection demonstrated that these cells acquired cytotoxic potential in vivo, even in the absence of IFN-gamma. Cytotoxic potential correlated with Fasl expression, and the cytotoxic activity of postinfection Tc17 cells was partially blocked by the addition of anti-FasL. Thus, Tc17 cells mediate VV clearance through expression of specific molecules associated with cytotoxicity but independent of an acquired Tc1 phenotype.

Temporal induction pattern of STAT4 target genes defines potential for Th1 lineage-specific programming.

STAT4 is a critical component in the development of inflammatory adaptive immune responses. It has been extensively characterized as a lineage-determining factor in Th1 development. However, the genetic program activated by STAT4 that results in an inflammatory cell type is not well defined. In this report, we use DNA isolated from STAT4-chromatin immunoprecipitation to perform chromatin immunoprecipitation-on-chip analysis of over 28,000 mouse gene promoters to identify STAT4 targets. We demonstrate that STAT4 binds multiple gene-sets that program distinct components of the Th1 lineage. Although many STAT4 target genes display STAT4-dependent IL-12-inducible expression, other genes displayed IL-12-induced histone modifications but lack induction, possibly due to high relative basal expression. In the subset of genes that STAT4 programs for expression in Th1 cells, IL-12-induced mRNA levels remain increased for a longer time than mRNA from genes that are not programmed. This suggests that STAT4 binding to target genes, while critical, is not the only determinant for STAT4-dependent gene programming during Th1 differentiation.

IL-23 promotes maintenance but not commitment to the Th17 lineage.

IL-23 plays a critical role establishing inflammatory immunity and enhancing IL-17 production in vivo. However, an understanding of how it performs those functions has been elusive. In this report, using an IL-17-capture technique, we demonstrate that IL-23 maintains the IL-17-secreting phenotype of purified IL-17(+) cells without affecting cell expansion or survival. IL-23 maintains the Th17 phenotype over multiple rounds of in vitro stimulation most efficiently in conjunction with IL-1beta. However, in contrast to Th1 and Th2 cells, the Th17 phenotype is not stable and when long-term IL-23-stimulated Th17 cultures are exposed to Th1- or Th2-inducing cytokines, the Th17 genetic program is repressed and cells that previously secreted IL-17 assume the cytokine secreting profile of other Th subsets. Thus, while IL-23 can maintain the Th17 phenotype, it does not promote commitment to an IL-17-secreting lineage.

Perioperative Mortality in Nonelderly Adult Patients With Cancer: A Population-based Study Evaluating Health Care Disparities in the United States According to Insurance Status.

OBJECTIVES: The purpose of this study was to evaluate whether insurance status predicts for perioperative mortality (death within 30 d of cancer-directed surgery) for the 20 most common surgically treated cancers. METHODS: The SEER database was examined for the 20 most common surgically resected cancers and included nonelderly adults, aged 18 to 64 years. The database was queried from 2007 to 2011, with a total of 506,722 patients included in the analysis. RESULTS: Insurance status for all patients were the following: non-Medicaid insurance (83%), any Medicaid (10%), uninsured (4%), and unknown (3%). In univariate analyses, predictors for perioperative mortality included insurance status (P<0.001), age (P=0.015), race (P<0.001), marital status (P<0.001), residence (P=0.002), percent of county below the federal poverty level (P<0.001), and median county-level income (P<0.001). Perioperative mortality was also associated with advanced disease (P<0.001). Under multivariate analysis, patients with either Medicaid (Cochran-Mantel-Haenszel odds ratio [CMH OR], 1.21; 95% confidence interval [CI], 1.14-1.29; P<0.001) or uninsured status (CMH OR, 1.56; 95% CI, 1.44-1.70; P<0.001) were more likely to die within 30 days of surgery compared with patients with non-Medicaid insurance. When comparing Medicaid with the uninsured, Medicaid patients had significantly lower rates of perioperative mortality when compared with the uninsured (CMH OR, 0.80; 95% CI, 0.73-0.89, P<0.001). CONCLUSIONS AND RELEVANCE: In the largest reported analysis of perioperative mortality evaluating the 20 most common surgically treated malignancies, patients with Medicaid coverage or without health insurance were more likely to die within 30 days of surgery, with the uninsured having the worst outcomes.

The Prognostic Value of BRAF, C-KIT, and NRAS Mutations in Melanoma Patients With Brain Metastases.

PURPOSE: Brain metastases are a common problem in patients with melanoma, but little is known about the effect of gene mutations on survival in these patients. METHODS AND MATERIALS: We created a retrospective multi-institutional database of 823 patients with melanoma and brain metastases diagnosed between 2006 and 2015. Clinical parameters, gene mutation status (BRAF, C-KIT, NRAS), and treatment were correlated with survival. Treatment patterns and outcomes were compared with a prior era (1985-2005). RESULTS: BRAF status was known in 584 of 823 patients (71%). BRAF, NRAS, and C-KIT mutations were present in 51%, 22%, and 11% of tested patients, respectively. The median time from primary diagnosis to brain metastasis was 32 months, and overall median survival (MS) from the time of initial treatment of brain metastases was 10 months. MS for BRAF-positive and BRAF-negative patients was 13 months and 9 months, respectively (P=.02). There was no significant difference in MS in patients with or without NRAS or C-KIT mutations. The time from primary diagnosis to brain metastasis did not vary by mutation and was not associated with survival after the diagnosis of brain metastases. MS for the 1985 to 2005 and 2006 to 2015 cohorts was 6.7 months and 10.0 months, respectively (P<.01). Reflecting treatment-trend changes, use of whole-brain radiation therapy decreased from 48% to 26% during this period. Among BRAF-positive patients, 71% received targeted BRAF and/or MEK inhibitors and 57% received some combination of targeted therapy, chemotherapy, and/or immunotherapy. CONCLUSIONS: For melanoma patients with brain metastases, BRAF-positive patients survive longer than BRAF-negative patients and overall survival has improved from 1985-2005 to 2006-2015.