Prospective, longitudinal study of risk factors for cancer-related distress in colorectal cancer survivors from prior to surgery until one year after surgery: Results from the ColoCare study

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Background: Although cancer-related distress is known to persist long after completion of colorectal cancer (CRC) treatment, factors related to distress are largely unexplored in CRC survivors. We examined changes over time and risk factors for distress in CRC patients over the first year after surgery. Methods: We included 212 CRC patients who consented pre-surgery, with data at 6 and 12 months post-surgery from the ColoCare Study in Heidelberg, Germany. Sociodemographic and lifestyle factors, social support and health-related quality of life (QOL) prior to surgery were evaluated as predictors of cancer-related distress. Distress was measured with the Cancer and Treatment Distress instrument (CTXD). Linear regression analyses examined associations between risk factors and distress. Results: Although overall mean of six distress subscales did not change from 6 to 12 months, distress subscale scores varied over time: health burden subscale score increased ( p < .001), while finances ( p = .004), medical demands ( p < .001), and identity ( p < .001) subscale scores decreased from 6 to 12 months. Uncertainty and family strain subscale scores did not change. Younger age, lower income, advanced cancer stage, poorer social support, and poorer baseline QOL scores predicted worse distress at 6 and 12 months. Conclusions: Cancer-related distress continues unresolved at 6 and 12 months post-surgery in this population of CRC survivors. Although some risk factors are difficult to alter, lack of social support may be modifiable and those at risk can be identified early after diagnosis. Screening for risk factors pre-surgery would allow for targeted interventions including strategies to improve resources for those with low support, thereby reducing long-term distress in CRC survivors.

Transcriptome Profiling of Adipose Tissue Reveals Depot-Specific Metabolic Alterations Among Patients with Colorectal Cancer

CONTEXT

Adipose tissue inflammation and dysregulated energy homeostasis are key mechanisms linking obesity and cancer. Distinct adipose tissue depots strongly differ in their metabolic profiles; however, comprehensive studies of depot-specific perturbations among patients with cancer are lacking.

OBJECTIVE

We compared transcriptome profiles of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) from patients with colorectal cancer and assessed the associations of different anthropometric measures with depot-specific gene expression.

DESIGN

Whole transcriptomes of VAT and SAT were measured in 233 patients from the ColoCare Study, and visceral and subcutaneous fat area were quantified via CT.

RESULTS

VAT compared with SAT showed elevated gene expression of cytokines, cell adhesion molecules, and key regulators of metabolic homeostasis. Increased fat area was associated with downregulated lipid and small molecule metabolism and upregulated inflammatory pathways in both compartments. Comparing these patterns between depots proved specific and more pronounced gene expression alterations in SAT and identified unique associations of integrins and lipid metabolism-related enzymes. VAT gene expression patterns that were associated with visceral fat area poorly overlapped with patterns associated with self-reported body mass index (BMI). However, subcutaneous fat area and BMI showed similar associations with SAT gene expression.

CONCLUSIONS

This large-scale human study demonstrates pronounced disparities between distinct adipose tissue depots and reveals that BMI poorly correlates with fat mass-associated changes in VAT. Taken together, these results provide crucial evidence for the necessity to differentiate between distinct adipose tissue depots for a correct characterization of gene expression profiles that may affect metabolic health of patients with colorectal cancer.

Publisher Correction: Shared heritability and functional enrichment across six solid cancers

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Multiplatform Urinary Metabolomics Profiling to Discriminate Cachectic from Non-Cachectic Colorectal Cancer Patients: Pilot Results from the ColoCare Study

Cachexia is a multifactorial syndrome that is characterized by loss of skeletal muscle mass in cancer patients. The biological pathways involved remain poorly characterized. Here, we compare urinary metabolic profiles in newly diagnosed colorectal cancer patients (stage I–IV) from the ColoCare Study in Heidelberg, Germany. Patients were classified as cachectic (n = 16), pre-cachectic (n = 13), or non-cachectic (n = 23) based on standard criteria on weight loss over time at two time points. Urine samples were collected pre-surgery, and 6 and 12 months thereafter. Fat and muscle mass area were assessed utilizing computed tomography scans at the time of surgery. N = 152 compounds were detected using untargeted metabolomics with gas chromatography–mass spectrometry and n = 154 features with proton nuclear magnetic resonance spectroscopy. Thirty-four metabolites were overlapping across platforms. We calculated differences across groups and performed discriminant and overrepresentation enrichment analysis. We observed a trend for 32 compounds that were nominally significantly different across groups, although not statistically significant after adjustment for multiple testing. Nineteen compounds could be identified, including acetone, hydroquinone, and glycine. Comparing cachectic to non-cachectic patients, higher levels of metabolites such as acetone (Fold change (FC) = 3.17; p = 0.02) and arginine (FC = 0.33; p = 0.04) were observed. The two top pathways identified were glycerol phosphate shuttle metabolism and glycine and serine metabolism pathways. Larger subsequent studies are needed to replicate and validate these results.

Plasma metabolites associated with colorectal cancer: A discovery-replication strategy

Colorectal cancer is known to arise from multiple tumorigenic pathways; however, the underlying mechanisms remain not completely understood. Metabolomics is becoming an increasingly popular tool in assessing biological processes. Previous metabolomics research focusing on colorectal cancer is limited by sample size and did not replicate findings in independent study populations to verify robustness of reported findings. Here, we performed a ultrahigh performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS) screening on EDTA plasma from 268 colorectal cancer patients and 353 controls using independent discovery and replication sets from two European cohorts (ColoCare Study: n = 180 patients/n = 153 controls; the Colorectal Cancer Study of Austria (CORSA) n = 88 patients/n = 200 controls), aiming to identify circulating plasma metabolites associated with colorectal cancer and to improve knowledge regarding colorectal cancer etiology. Multiple logistic regression models were used to test the association between disease state and metabolic features. Statistically significant associated features in the discovery set were taken forward and tested in the replication set to assure robustness of our findings. All models were adjusted for sex, age, BMI and smoking status and corrected for multiple testing using False Discovery Rate. Demographic and clinical data were abstracted from questionnaires and medical records.

Effects and moderators of exercise on sleep in adults with cancer: Individual patient data and aggregated meta-analyses

OBJECTIVES

To evaluate the effects of exercise interventions on sleep disturbances and sleep quality in patients with mixed cancer diagnoses, and identify demographic, clinical, and intervention-related moderators of these effects.

METHODS

Individual patient data (IPD) and aggregated meta-analyses of randomized controlled trials (RCTs). Using data from the Predicting OptimaL cAncer RehabIlitation and Supportive care project, IPD of 2173 adults (mean age = 54.8) with cancer from 17 RCTs were analyzed. A complementary systematic search was conducted (until November 2018) to study the overall effects and test the representativeness of analyzed IPD. Effect sizes of exercise effects on self-reported sleep outcomes were calculated for all included RCTs. Linear mixed-effect models were used to evaluate the effects of exercise on post-intervention outcome values, adjusting for baseline values. Moderator effects were studied by testing interactions for demographic, clinical and intervention-related characteristics.

RESULTS

For all 27 eligible RCTs from the updated search, exercise interventions significantly decreased sleep disturbances in adults with cancer (g = -0.09, 95% CI [-0.16; -0.02]). No significant effect was obtained for sleep quality. RCTs included in IPD analyses constituted a representative sample of the published literature. The intervention effects on sleep disturbances were not significantly moderated by any demographic, clinical, or intervention-related factor, nor by sleep disturbances.

CONCLUSIONS

This meta-analysis provides some evidence that, compared to control conditions, exercise interventions may improve sleep disturbances, but not sleep quality, in cancer patients, although this effect is of a small magnitude. Among the investigated variables, none was found to significantly moderate the effect of exercise interventions on sleep disturbances.

Racial/Ethnic Patterns of Young-Onset Noncardia Gastric Cancer

Increasing noncardia gastric cancer incidence rates among individuals age younger than 50 years have gained much attention, particularly as causes remain unknown. Using population-based NIH/NCI's Surveillance, Epidemiology, and End Results (SEER) program data from 2007 to 2015, multivariable logistic regression was used to quantify associations between race/ethnicity and clinicodemographic features among young-onset noncardia gastric cancer patients. A total of 2,872 individuals ages 20 to 49 years were diagnosed with primary noncardia gastric cancer. Age at diagnosis, insurance status, anatomic subsite, American Joint Committee on Cancer (AJCC) clinical stage, histologic type, tumor grade, surgery, and county-level smoking prevalence differed by race/ethnicity (all P ≤ 0.003). Compared with non-Hispanic whites, Hispanics were more likely to be diagnosed at younger ages [odds ratio (OR) = 0.97; 95% confidence intervals (CI), 0.95-0.99], on Medicaid/uninsured (OR = 3.83; 95% CI, 2.89-5.08), diagnosed with higher grade tumors (OR = 1.93; 95% CI, 1.32-2.84), and less likely to undergo surgery (OR = 0.62; 95% CI, 0.44-0.88) or to reside in counties with higher smoking prevalence (OR = 0.15; 95% CI, 0.11-0.21) after adjustment for sex, subsite, and histologic type. Asian/Pacific Islanders were more likely to be female (OR = 1.40; 95% CI, 1.04-1.88), and less likely to be diagnosed with metastatic disease (OR = 0.59; 95% CI, 0.37-0.95) or to reside in counties with higher smoking prevalence (OR = 0.13; 95% CI, 0.08-0.19). Approximately two in every five patients with young-onset noncardia gastric cancer are Hispanic. Further investigation into the molecular heterogeneity of young-onset noncardia gastric cancers by race/ethnicity to understand etiologies underlying this rising disease epidemic is warranted. This population-based cohort study sheds light that biological and environmental factors may partly underlie race/ethnicity-related differences in young-onset noncardia gastric cancer susceptibility and outcomes.

No Evidence for Effect of Exercise on Transcriptome of NK Cells in Breast Cancer Patients Undergoing Adjuvant Therapy: Results From a Pilot Study

Background

Mobilization and activation of natural killer cells (NK cells) have been hypothesized to contribute to observed protective effects of exercise on cancer development and progression. Some evidence exists for acute effects of aerobic exercise on NK cell mobilization and function, i.e., alteration of the gene expression profile of NK cells. Yet, the chronic effects of exercise training, and effects of other modalities than endurance exercise are still understudied. Here, we investigated the chronic effects of a 12-week resistance exercise program on NK cell gene expression in breast cancer patients undergoing adjuvant chemo- or radiotherapy.

Methods

Breast cancer patients were randomly assigned to either a 12-week resistance exercise program or a relaxation control group concomitant to adjuvant therapy. In a subsample of 19 participants, RNA was extracted from magnet bead isolated NK cells and subsequently analyzed for differential gene expression using microarray Illumina HumanHT-12 v4 before and after the intervention.

Results

After chronic exercise intervention several genes showed higher differential expression compared to the control group. However, after correction for multiple testing, baseline-adjusted analyses of covariance indicated no significant differences between the intervention and the control group with regard to the gene expression profile.

Discussion

Our findings suggest that 12-week resistance-exercise did not alter the gene expression profile of NK cells in breast cancer patients undergoing adjuvant therapy on the long term. Further studies with larger sample sizes and specifically designed to investigate whether exercise-induced changes in NK cell function are attributed to acute effects are warranted.

Abstract 3283: Associations of change in BMI before surgery with disease-free and overall survival in colorectal cancer patients: Results from the ColoCare Cohort

BACKGROUND Body weight in colorectal cancer patients may change substantially before and after diagnosis and treatment. The prognostic significance of pre-surgery weight loss is still unclear. We investigated the association of pre-surgery weight loss with clinical outcomes in colorectal cancer patients.

METHODS We used prospectively collected data from n=148 newly diagnosed colorectal cancer patients (stage I-IV) from the ColoCare Cohort. Data on body mass index (BMI; (kg)/ m2) 1 year before surgery and at the time of surgery were collected. We calculated BMI differences between these time points. We applied Cox proportional hazard models to investigate associations of BMI change (continuous), biological sex (male, female) and tumor stage (I, II, III, IV) and neoadjuvant chemo- and/or radiotherapy (no/yes).

RESULTS After 24 months of follow-up n=22 patients were deceased and n=19 patients had a recurrence. Pre-surgery change in BMI was associated with poorer overall and disease-free survival: for every loss in one unit in BMI patients had a 47% increase in risk of overall death: Hazard Ratio (HR): 1.47; 95% confidence interval (CI) (1.21-1.76), p=0.0001 and a 44% increase in risk for either death or recurrence: HR: 1.44; 95% CI (1.19-1.73), p=0.0002.

CONCLUSIONS Pre-surgery weight change is, independently of tumor stage, age, biological sex and neoadjuvant therapy, associated with long-term clinical outcomes in colorectal cancer survivors.

Citation Format: Jennifer Ose, Biljana Gigic, Tengda Lin, Juergen Boehm, Petra Schrotz-King, Petra Schrotz-King, Sheetal Hardikar, Caroline Himbert, Martin Schneider, Alexis Ulrich, Cornelia M. Ulrich. Associations of change in BMI before surgery with disease-free and overall survival in colorectal cancer patients: Results from the ColoCare Cohort [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 3283.

Correction to: Genetic variant predictors of gene expression provide new insight into risk of colorectal cancer

Every author has erroneously been assigned to the affiliation "62". The affiliation 62 belongs to the author Graham Casey.

Tumor suppressive autophagy in intestinal stem cells controls gut homeostasis

We recently found that re-routing intracellular vesicle traffic by suppressing macroautophagy/autophagy or endocytosis genes drastically deregulates Drosophila intestinal stem cell (ISC) proliferation, leading to massive gut hyperplasia that has a negative impact upon lifespan. Beginning with the poorly characterized Snx (sorting nexin) genes, we surveyed a broad set of genes in the endocytosis-autophagy network and found that most of them have this effect. We then discovered that deregulated Egfr-Ras85D/Ras1-mitogen-activated protein kinase signaling is the primary trigger for ISC proliferation upon disruption of this network and determined that in the mutants, ligand-activated receptors were stabilized and recycled to the cell surface via Rab11-dependent endosomes, rather than being degraded via autophagosomes. We profiled the mutational landscape for orthologous network genes in human cancers using The Cancer Genome Atlas (TCGA), and revealed strong, novel associations with distinct genomic and epigenomic subtypes of colorectal cancer.

The Consortium of Metabolomics Studies (COMETS): Metabolomics in 47 Prospective Cohort Studies

The Consortium of Metabolomics Studies (COMETS) was established in 2014 to facilitate large-scale collaborative research on the human metabolome and its relationship with disease etiology, diagnosis, and prognosis. COMETS comprises 47 cohorts from Asia, Europe, North America, and South America that together include more than 136,000 participants with blood metabolomics data on samples collected from 1985 to 2017. Metabolomics data were provided by 17 different platforms, with the most frequently used labs being Metabolon, Inc. (14 cohorts), the Broad Institute (15 cohorts), and Nightingale Health (11 cohorts). Participants have been followed for a median of 23 years for health outcomes including death, cancer, cardiovascular disease, diabetes, and others; many of the studies are ongoing. Available exposure-related data include common clinical measurements and behavioral factors, as well as genome-wide genotype data. Two feasibility studies were conducted to evaluate the comparability of metabolomics platforms used by COMETS cohorts. The first study showed that the overlap between any 2 different laboratories ranged from 6 to 121 metabolites at 5 leading laboratories. The second study showed that the median Spearman correlation comparing 111 overlapping metabolites captured by Metabolon and the Broad Institute was 0.79 (interquartile range, 0.56-0.89).

Association between pretreatment Fusobacterium nucleatum and cancer pain at six months postsurgery in newly diagnosed colorectal cancer patients: Results from the ColoCare Study

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Background: Pain is a prevalent, debilitating symptom in more than half of cancer patients. Accumulating evidence suggests a bi-directional relationship between gut microbiota and pain, potentially via inflammation and oxidative stress. Fusobacterium nucleatum (Fn), a pro-inflammatory anaerobic bacterium, is frequently detected in colorectal cancer (CRC) patients. To date, no study has identified a relationship between Fn and cancer pain in CRC patients. We investigated the associations between pre-treatment Fn and cancer pain at 6 months post-surgery in CRC patients. Methods: We utilized pre-surgery stool samples collected from 80 prospectively followed, newly diagnosed CRC patients recruited from the German site of the international ColoCare Study. Eligible patients were neo-adjuvant treatment naïve and did not use antibiotics for at least 1 month before stool collection. Fn DNA was assessed via quantitative real-time polymerase chain reaction. Patients were median split into Fn-high (>17.27; n=40) or Fn-low (≤17.27; n=40). Cancer pain was assessed using the 2 pain symptom items from the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core-30 (lower score=lower pain) at pre- and 6 months post-surgery. Results: Before surgery, 48% of all patients reported any pain. At 6 months post-surgery, we observed a decrease in cancer pain by 33% for Fn-low, while there was an increase in cancer pain by 41% for Fn-high. After controlling for pre-surgery cancer pain in ANCOVA model, we observed significantly higher mean cancer pain at 6 months post-surgery in the Fn-high group vs. the Fn-low group (24.07 vs. 13.44; effect size, ES=0.45; p=0.04). These results were maintained even after controlling for age, sex, tumor stage and site, adjuvant chemotherapy, BMI, physical activity, and any pain medications (29.11 vs. 16.55; ES=0.53; p=0.03). Conclusions: These findings suggest that high Fn is an independent predictor of cancer pain at 6 months post-surgery in colorectal cancer patients. Further research is needed to confirm and understand the mechanisms of these results. Funding: NCI U01 CA206110.

Inflammation- and angiogenesis-related biomarkers are correlated with cancer-related fatigue in colorectal cancer patients: Results from the ColoCare Study

Cancer-related fatigue is one of the most common side effects of colorectal cancer treatment and is affected by biomedical factors. We investigated the association of inflammation- and angiogenesis-related biomarkers with cancer-related fatigue. Pre-surgery (baseline) serum samples were obtained from n = 236 newly diagnosed colorectal cancer patients. Meso Scale Discovery assays were performed to measure levels of biomarkers for inflammation and angiogenesis (CRP, SAA, IL-6, IL-8, MCP-1, sICAM-1, sVCAM-1, TNFα, VEGFA and VEGFD). Cancer-related fatigue was assessed with the EORTC QLQ-30 questionnaire at baseline and 6 and 12 months post-surgery. We tested associations using Spearman's partial correlations and logistic regression analyses, adjusting for age, sex and body mass index. sICAM-1 and VEGFD showed a significant positive correlation with cancer-related fatigue at baseline and 6-, and 12-month follow-up (sICAM-1: r = 0.19, p = 0.010; r = 0.24, p = 0.004; r = 0.25, p = 0.006; VEGFD: r = 0.20, p = 0.006; r = 0.15, p = 0.06; r = 0.23, p = 0.01 respectively). Biomarkers of inflammation and angiogenesis measured prior to surgery are associated with cancer-related fatigue in colorectal cancer patients throughout various time points. Our results suggest the involvement of overexpressed sICAM-1 and VEGFD in the development of fatigue.

Changes in Pancreatic Fat Content Following Diet-Induced Weight Loss

Background: Obesity can lead to ectopic pancreatic fat accumulation and increase the risk for type 2 diabetes. Smaller intervention trials have shown a decrease in pancreatic fat content (PFC) with weight loss, and we intended to investigate the effects of weight loss on PFC in a larger trial. Methods: Data from the HELENA-Trial, a randomized controlled trial (RCT) among 137 non-diabetic obese adults were used. The study cohort was classified into 4 quartiles based on weight change between baseline and 12 weeks post-intervention. Changes in PFC (baseline, 12 weeks and 50 weeks post-intervention) upon weight loss were analyzed by linear mixed models. Spearman’s coefficients were used to obtain correlations between anthropometric parameters, blood biochemical markers, and PFC. Results: At baseline, PFC only showed a significant correlation with visceral adipose tissue (VAT) (r = 0.41). Relative changes in PFC were significantly (p = 0.01) greater in Q4 (−30.8 ± 5.7%) than in Q1 (1.3 ± 6.7%). These differences remained similar after one year. However, when adjusting the statistical analyses for changes in VAT, the differences in PFC between Q1 and Q4 were no longer statistically significant. Conclusion: Weight loss is associated with a decrease in PFC. However, the reduction of PFC is not independent from reductions in VAT. Unlike VAT, PFC was not associated with metabolic biomarkers.

An SH3PX1-Dependent Endocytosis-Autophagy Network Restrains Intestinal Stem Cell Proliferation by Counteracting EGFR-ERK Signaling

The effect of intracellular vesicle trafficking on stem-cell behavior is largely unexplored. We screened the Drosophila sorting nexins (SNXs) and discovered that one, SH3PX1, profoundly affects gut homeostasis and lifespan. SH3PX1 restrains intestinal stem cell (ISC) division through an endocytosis-autophagy network that includes Dynamin, Rab5, Rab7, Atg1, 5, 6, 7, 8a, 9, 12, 16, and Syx17. Blockages in this network stabilize ligand-activated EGFRs, recycling them via Rab11-dependent endosomes to the plasma membrane. This hyperactivated ERK, calcium signaling, and ER stress, autonomously stimulating ISC proliferation. The excess divisions induced epithelial stress, Yki activity, and Upd3 and Rhomboid production in enterocytes, catalyzing feedforward ISC hyperplasia. Similarly, blocking autophagy increased ERK activity in human cells. Many endocytosis-autophagy genes are mutated in cancers, most notably those enriched in microsatellite instable-high and KRAS-wild-type colorectal cancers. Disruptions in endocytosis and autophagy may provide an alternative route to RAS-ERK activation, resulting in EGFR-dependent cancers.

Metagenomic analysis of colorectal cancer datasets identifies cross-cohort microbial diagnostic signatures and a link with choline degradation

Several studies have investigated links between the gut microbiome and colorectal cancer (CRC), but questions remain about the replicability of biomarkers across cohorts and populations. We performed a meta-analysis of five publicly available datasets and two new cohorts and validated the findings on two additional cohorts, considering in total 969 fecal metagenomes. Unlike microbiome shifts associated with gastrointestinal syndromes, the gut microbiome in CRC showed reproducibly higher richness than controls (P < 0.01), partially due to expansions of species typically derived from the oral cavity. Meta-analysis of the microbiome functional potential identified gluconeogenesis and the putrefaction and fermentation pathways as being associated with CRC, whereas the stachyose and starch degradation pathways were associated with controls. Predictive microbiome signatures for CRC trained on multiple datasets showed consistently high accuracy in datasets not considered for model training and independent validation cohorts (average area under the curve, 0.84). Pooled analysis of raw metagenomes showed that the choline trimethylamine-lyase gene was overabundant in CRC (P = 0.001), identifying a relationship between microbiome choline metabolism and CRC. The combined analysis of heterogeneous CRC cohorts thus identified reproducible microbiome biomarkers and accurate disease-predictive models that can form the basis for clinical prognostic tests and hypothesis-driven mechanistic studies.

Meta-analysis of fecal metagenomes reveals global microbial signatures that are specific for colorectal cancer

Association studies have linked microbiome alterations with many human diseases. However, they have not always reported consistent results, thereby necessitating cross-study comparisons. Here, a meta-analysis of eight geographically and technically diverse fecal shotgun metagenomic studies of colorectal cancer (CRC, n = 768), which was controlled for several confounders, identified a core set of 29 species significantly enriched in CRC metagenomes (false discovery rate (FDR) < 1 × 10^-5). CRC signatures derived from single studies maintained their accuracy in other studies. By training on multiple studies, we improved detection accuracy and disease specificity for CRC. Functional analysis of CRC metagenomes revealed enriched protein and mucin catabolism genes and depleted carbohydrate degradation genes. Moreover, we inferred elevated production of secondary bile acids from CRC metagenomes, suggesting a metabolic link between cancer-associated gut microbes and a fat- and meat-rich diet. Through extensive validations, this meta-analysis firmly establishes globally generalizable, predictive taxonomic and functional microbiome CRC signatures as a basis for future diagnostics.

Genetic variant predictors of gene expression provide new insight into risk of colorectal cancer

Genome-wide association studies have reported 56 independently associated colorectal cancer (CRC) risk variants, most of which are non-coding and believed to exert their effects by modulating gene expression. The computational method PrediXcan uses cis-regulatory variant predictors to impute expression and perform gene-level association tests in GWAS without directly measured transcriptomes. In this study, we used reference datasets from colon (n = 169) and whole blood (n = 922) transcriptomes to test CRC association with genetically determined expression levels in a genome-wide analysis of 12,186 cases and 14,718 controls. Three novel associations were discovered from colon transverse models at FDR ≤ 0.2 and further evaluated in an independent replication including 32,825 cases and 39,933 controls. After adjusting for multiple comparisons, we found statistically significant associations using colon transcriptome models with TRIM4 (discovery P = 2.2 × 10- 4, replication P = 0.01), and PYGL (discovery P = 2.3 × 10- 4, replication P = 6.7 × 10- 4). Interestingly, both genes encode proteins that influence redox homeostasis and are related to cellular metabolic reprogramming in tumors, implicating a novel CRC pathway linked to cell growth and proliferation. Defining CRC risk regions as one megabase up- and downstream of one of the 56 independent risk variants, we defined 44 non-overlapping CRC-risk regions. Among these risk regions, we identified genes associated with CRC (P < 0.05) in 34/44 CRC-risk regions. Importantly, CRC association was found for two genes in the previously reported 2q25 locus, CXCR1 and CXCR2, which are potential cancer therapeutic targets. These findings provide strong candidate genes to prioritize for subsequent laboratory follow-up of GWAS loci. This study is the first to implement PrediXcan in a large colorectal cancer study and findings highlight the utility of integrating transcriptome data in GWAS for discovery of, and biological insight into, risk loci.

Similar Weight Loss Induces Greater Improvements in Insulin Sensitivity and Liver Function among Individuals with NAFLD Compared to Individuals without NAFLD

BACKGROUND

Preliminary evidence suggests that weight loss among obese has differential metabolic effects depending on the presence of non-alcoholic fatty liver disease (NAFLD). We assessed whether NAFLD predisposes to differential changes in liver fat content, liver function, and metabolic parameters upon diet-induced weight loss in a 50-week intervention trial.

METHODS

143 overweight and obese non-smokers underwent a 12-week dietary intervention and a 38-week follow-up. Diet-induced changes in anthropometric measures, circulating biomarkers, and magnetic resonance (MR)-derived liver fat content and adipose tissue volumes were evaluated by mixed linear models stratifying by NAFLD at baseline.

RESULTS

The prevalence of NAFLD at baseline was 52%. Diet-induced weight loss after 12 (NAFLD: 4.8 ± 0.5%, No NAFLD: 5.1 ± 0.5%) and 50 weeks (NAFLD: 3.5 ± 0.7%, No NAFLD: 3.5 ± 0.9%) was similar in both groups, while the decrease in liver fat was significantly greater in the NAFLD group (week 12: 32.9 ± 9.5% vs. 6.3 ± 4.0%; week 50: 23.3 ± 4.4% vs. 5.0 ± 4.2%). Decreases in biomarkers of liver dysfunction (GGT, ALT, AST) and HOMA IR were also significantly greater in the NAFLD group. Other metabolic parameters showed no significant differences.

CONCLUSION

Our data suggest that individuals with NAFLD show greater improvements of liver function and insulin sensitivity after moderate diet-induced weight loss than individuals without NAFLD.

Novel Common Genetic Susceptibility Loci for Colorectal Cancer

BACKGROUND

Previous genome-wide association studies (GWAS) have identified 42 loci (P < 5 × 10-8) associated with risk of colorectal cancer (CRC). Expanded consortium efforts facilitating the discovery of additional susceptibility loci may capture unexplained familial risk.

METHODS

We conducted a GWAS in European descent CRC cases and control subjects using a discovery-replication design, followed by examination of novel findings in a multiethnic sample (cumulative n = 163 315). In the discovery stage (36 948 case subjects/30 864 control subjects), we identified genetic variants with a minor allele frequency of 1% or greater associated with risk of CRC using logistic regression followed by a fixed-effects inverse variance weighted meta-analysis. All novel independent variants reaching genome-wide statistical significance (two-sided P < 5 × 10-8) were tested for replication in separate European ancestry samples (12 952 case subjects/48 383 control subjects). Next, we examined the generalizability of discovered variants in East Asians, African Americans, and Hispanics (12 085 case subjects/22 083 control subjects). Finally, we examined the contributions of novel risk variants to familial relative risk and examined the prediction capabilities of a polygenic risk score. All statistical tests were two-sided.

RESULTS

The discovery GWAS identified 11 variants associated with CRC at P < 5 × 10-8, of which nine (at 4q22.2/5p15.33/5p13.1/6p21.31/6p12.1/10q11.23/12q24.21/16q24.1/20q13.13) independently replicated at a P value of less than .05. Multiethnic follow-up supported the generalizability of discovery findings. These results demonstrated a 14.7% increase in familial relative risk explained by common risk alleles from 10.3% (95% confidence interval [CI] = 7.9% to 13.7%; known variants) to 11.9% (95% CI = 9.2% to 15.5%; known and novel variants). A polygenic risk score identified 4.3% of the population at an odds ratio for developing CRC of at least 2.0.

CONCLUSIONS

This study provides insight into the architecture of common genetic variation contributing to CRC etiology and improves risk prediction for individualized screening.

Shared heritability and functional enrichment across six solid cancers

Quantifying the genetic correlation between cancers can provide important insights into the mechanisms driving cancer etiology. Using genome-wide association study summary statistics across six cancer types based on a total of 296,215 cases and 301,319 controls of European ancestry, here we estimate the pair-wise genetic correlations between breast, colorectal, head/neck, lung, ovary and prostate cancer, and between cancers and 38 other diseases. We observed statistically significant genetic correlations between lung and head/neck cancer (rg = 0.57, p = 4.6 × 10-8), breast and ovarian cancer (rg = 0.24, p = 7 × 10-5), breast and lung cancer (rg = 0.18, p =1.5 × 10-6) and breast and colorectal cancer (rg = 0.15, p = 1.1 × 10-4). We also found that multiple cancers are genetically correlated with non-cancer traits including smoking, psychiatric diseases and metabolic characteristics. Functional enrichment analysis revealed a significant excess contribution of conserved and regulatory regions to cancer heritability. Our comprehensive analysis of cross-cancer heritability suggests that solid tumors arising across tissues share in part a common germline genetic basis.

Discovery of common and rare genetic risk variants for colorectal cancer

To further dissect the genetic architecture of colorectal cancer (CRC), we performed whole-genome sequencing of 1,439 cases and 720 controls, imputed discovered sequence variants and Haplotype Reference Consortium panel variants into genome-wide association study data, and tested for association in 34,869 cases and 29,051 controls. Findings were followed up in an additional 23,262 cases and 38,296 controls. We discovered a strongly protective 0.3% frequency variant signal at CHD1. In a combined meta-analysis of 125,478 individuals, we identified 40 new independent signals at P < 5 × 10-8, bringing the number of known independent signals for CRC to ~100. New signals implicate lower-frequency variants, Krüppel-like factors, Hedgehog signaling, Hippo-YAP signaling, long noncoding RNAs and somatic drivers, and support a role for immune function. Heritability analyses suggest that CRC risk is highly polygenic, and larger, more comprehensive studies enabling rare variant analysis will improve understanding of biology underlying this risk and influence personalized screening strategies and drug development.

CT-Quantified Adipose Tissue Distribution: Risk or Protective Factor for Complications after Rectal Cancer Surgery?

PURPOSE

Obesity is associated with increased incidence and mortality in rectal cancer (RC). However, an obesity paradox in the sense of a protective effect of obesity is discussed controversially. We evaluated whether adipose tissue distribution has an impact on medical (MC) and surgical complications (SC) after RC surgery.

METHODS

A total of 296 RC patients underwent oncological surgery and multidetector CT with quantification of total (TAT), visceral (VAT), and subcutaneous adipose tissue (SAT). Logistic regressions on SC (anastomotic leakage [n = 26], wound infection [n = 58], bleeding [n = 12], abscess [n = 32], bladder dysfunction [n = 24], burst abdomen [n = 10]), and MC (pulmonary [n = 22], cardiac [n = 18], urinary tract infection [n = 9], sepsis [n = 5]) were performed.

RESULTS

High pelvicVAT was associated with reduced risk for overall SC (OR = 0.915, p = 0.012) and anastomotic leakage (OR = 0.587, p = 0.024, CI: 0.369/0.934). In contrast, CT-quantified obesity was associated with increased risk for wound infection, bladder dysfunction, burst abdomen, overall MC, and cardiac complications (ORs up to 1.423). BMI was not associated with any SC or MC.

CONCLUSION

An obesity paradox with a protective effect of CT-quantified adipose tissue was confirmed for anastomotic leakage and overall SC. In contrast, high adipose tissue was associated with higher risk for other SC and MC. These results show a more complex influence of body composition on MC and SC. CT-quantified obesity is able to provide deeper insights to explain the obesity paradox beyond BMI.