Intakes of dietary folate and other B vitamins are associated with risks of esophageal adenocarcinoma, Barrett's esophagus, and reflux esophagitis

Folate is implicated in carcinogenesis via effects on DNA synthesis, repair, and methylation. Efficient folate metabolism requires other B vitamins and is adversely affected by smoking and alcohol. Esophageal adenocarcinoma (EAC) may develop through a process involving inflammation [reflux esophagitis (RE)] leading to metaplasia [Barrett’s esophagus (BE)] and carcinoma. Within a population-based, case-control study, we investigated associations between dietary folate and related factors and risks of EAC, BE, and RE. EAC and BE cases had histologically confirmed disease; RE cases had endoscopically visible inflammation. Controls, age-sex frequency matched to EAC cases, were selected through population and general practice registers. Participants underwent structured interviews and completed food-frequency questionnaires. Multivariate ORs and 95% CIs were computed using logistic regression. A total of 256 controls and 223 EAC, 220 BE, and 219 RE cases participated. EAC risk decreased with increasing folate intake (OR highest vs. lowest = 0.56; 95% CI: 0.31, 1.00; P-trend < 0.01). Similar trends were found for BE (P-trend < 0.01) and RE (P-trend = 0.01). Vitamin B-6 intake was significantly inversely related to risks of all 3 lesions. Riboflavin intake was inversely associated with RE. Vitamin B-12 intake was positively associated with EAC. For EAC, there was a borderline significant interaction between folate intake and smoking (P-interaction = 0.053); compared with nonsmokers with high (≥median) folate intake, current smokers with low intakes (<median) had an 8-fold increased risk (OR: 8.15; 95% CI: 3.61, 18.40). The same group had increased BE risk (OR: 2.93; 95% CI: 1.24, 6.92; P-interaction = 0.12). Folate and other dietary methyl-group factors are implicated in the etiology of EAC and its precursors.

Transit timing variations in WASP-10b induced by stellar activity

The hot-JupiterWASP-10bwas reported by Maciejewski et al. to showtransit timing variations (TTVs) with an amplitude of ~3.5 min. These authors proposed that the observed TTVs were caused by a 0.1M_Jup perturbing companion with an orbital period of ~5.23 d, and hence, close to the outer 5:3 mean-motion resonance with WASP-10b. To test this scenario, we present eight new transit light curves of WASP-10b obtained with the Faulkes Telescope North and the Liverpool Telescope. The new light curves, together with 22 previously published ones, were modelled with a Markov Chain Monte Carlo transit fitting code. Transit depth differences reported forWASP-10b are thought to be due to starspot-induced brightness modulation of the host star. Assuming the star is brighter at the activity minimum, we favour a small planetary radius. We find Rp = 1.039^+0.043 _-0.049R_Jup in agreement with Johnson et al. and Maciejewski et al. Recent studies find no evidence for a significant eccentricity in this system. We present consistent system parameters for a circular orbit and refine the orbital ephemeris ofWASP-10b. Our homogeneously derived transit times do not support the previous claimed TTV signal, which was strongly dependent on two previously published transits that have been incorrectly normalized. Nevertheless, a linear ephemeris is not a statistically good fit to the transit times of WASP-10b. We show that the observed transit time variations are due to spot occultation features or systematics. We discuss and exemplify the effects of occultation spot features in the measured transit times and show that despite spot occultation during egress and ingress being difficult to distinguish in the transit light curves, they have a significant effect in the measured transit times. We conclude that if we account for spot features, the transit times of WASP-10b are consistent with a linear ephemeris with the exception of one transit (epoch 143) which is a partial transit. Therefore, there is currently no evidence for the existence of a companion to WASP-10b. Our results support the lack of TTVs of hot-Jupiters reported for the Kepler sample. 

Aristarchos RISE2: A Wide-Field Fast Imager for Exoplanet Transit Timing

The detection of exoplanets is currently of great topical interest in astronomy. The Rapid Imager for Surveys of Exoplanets 2 (RISE2) camera will be built for exoplanet studies and in particular for detection of transit timing variations (TTV) induced by the presence of a third body in the system. It will be identical to RISE which has been running successfully on the 2m Liverpool Telescope since 2008 but modified for the 2.3m ARISTARCHOS telescope. For TTV work the RISE/LT combination is regularly producing timings with accuracy <10 seconds making it the best suited instrument for this work. Furthermore, RISE2/AT has the added benefit of being located at a significantly different longitude to the LT/RISE on La Palma, hence extending the transit coverage.

Influence of sex on the survival of patients with esophageal cancer

PURPOSE: The prognostic value of sex for esophageal cancer survival is currently unclear, and growing data suggest that hormonal influences may account for incidence disparities between men and women. Therefore, moving from the hypothesis that hormones could affect the prognosis of patients with esophageal cancer, we investigated the primary hypothesis that sex is associated with survival and the secondary hypotheses that the relationship between sex and survival depends, at least in part, on age, histology, and race/ethnicity.

PATIENTS AND METHODS: By using the SEER databases from 1973 to 2007, we identified 13,603 patients (34%) with metastatic esophageal cancer (MEC) and 26,848 patients (66%) with locoregional esophageal cancer (LEC). Cox proportional hazards model for competing risks were used for analyses.

RESULTS: In the multivariate analysis, women had longer esophageal cancer-specific survival (ECSS) than men in both MEC (hazard ratio [HR], 0.949; 95% CI, 0.905 to 0.995; P = .029) and LEC (HR, 0.920; 95% CI, 0.886 to 0.955; P < .001) cohorts. When age and histology were accounted for, there was no difference for ECSS between men and women with adenocarcinoma. In contrast, women younger than age 55 years (HR, 0.896; 95% CI, 0.792 to 1.014; P = .081) and those age 55 years or older (HR, 0.905; 95% CI, 0.862 to 0.950; P < .001) with squamous cell LEC had longer ECSS than men. In the squamous cell MEC cohort, only women younger than age 55 years had longer ECSS (HR, 0.823; 95% CI, 0.708 to 0.957; P = .011) than men.

CONCLUSION: Sex is an independent prognostic factor for patients with LEC or MEC. As secondary hypotheses, in comparison with men, women age 55 years or older with squamous cell LEC and women younger than age 55 years with squamous cell MEC have a significantly better outcome. These last two findings need further validation.

Pleiotropic analysis of cancer risk loci on esophageal adenocarcinoma risk

Background: Several cancer-associated loci identified from genome-wide association studies (GWAS) have been associated with risks of multiple cancer sites, suggesting pleiotropic effects. We investigated whether GWAS-identified risk variants for other common cancers are associated with risk of esophageal adenocarcinoma (EA) or its precursor, Barrett's esophagus. 

Methods: We examined the associations between risks of EA and Barrett's esophagus and 387 SNPs that have been associated with risks of other cancers, by using genotype imputation data on 2,163 control participants and 3,885 (1,501 EA and 2,384 Barrett's esophagus) case patients from the Barrett's and Esophageal Adenocarcinoma Genetic Susceptibility Study, and investigated effect modification by smoking history, body mass index (BMI), and reflux/heartburn. 

Results: After correcting for multiple testing, none of the tested 387 SNPs were statistically significantly associated with risk of EA or Barrett's esophagus. No evidence of effect modification by smoking, BMI, or reflux/heartburn was observed. 

Conclusions: Genetic risk variants for common cancers identified from GWAS appear not to be associated with risks of EA or Barrett's esophagus. 

Impact: To our knowledge, this is the first investigation of pleiotropic genetic associations with risks of EA and Barrett's esophagus.

Transit Observations of the Hot Jupiter HD 189733b at X-Ray Wavelengths

We present new X-ray observations obtained with Chandra ACIS-S of the HD 189733 system, consisting of a K-type star orbited by a transiting Hot Jupiter and an M-type stellar companion. We report a detection of the planetary transit in soft X-rays with a significantly deeper transit depth than observed in the optical. The X-ray data favor a transit depth of 6%-8%, versus a broadband optical transit depth of 2.41%. While we are able to exclude several possible stellar origins for this deep transit, additional observations will be necessary to fully exclude the possibility that coronal inhomogeneities influence the result. From the available data, we interpret the deep X-ray transit to be caused by a thin outer planetary atmosphere which is transparent at optical wavelengths, but dense enough to be opaque to X-rays. The X-ray radius appears to be larger than the radius observed at far-UV wavelengths, most likely due to high temperatures in the outer atmosphere at which hydrogen is mostly ionized. We furthermore detect the stellar companion HD 189733B in X-rays for the first time with an X-ray luminosity of log LX = 26.67 erg s-1. We show that the magnetic activity level of the companion is at odds with the activity level observed for the planet-hosting primary. The discrepancy may be caused by tidal interaction between the Hot Jupiter and its host star.