Plasma Concentrations of Gut Hormones Acyl Ghrelin and Peptide YY and Subsequent Risk of Colorectal Cancer and Molecular Tumor Subtypes.

Obesity and metabolic dysfunction are implicated in colorectal cancer development. Appetite-regulating gut hormones might have a role in colorectal cancer risk. We investigated whether circulating levels of the gut hormones ghrelin (analyzed as acyl ghrelin) and Peptide YY (PYY) were associated with subsequent colorectal cancer risk, including clinical and molecular tumor subtypes. We also provide descriptive data on these hormones in relation to background participant characteristics and metabolic biomarkers. This population-based study included 1,010 matched case-control pairs with a median of 12.3 years of follow-up. Acyl ghrelin and PYY were measured by multiplex immunoassay. Data on KRAS and BRAF mutations and microsatellite instability (MSI) status were available for 704 and 708 cases, respectively. Conditional logistic regression models estimated association to colorectal cancer risk. Partial correlation and linear regression were used to investigate relationships between background and metabolic variables and variation in plasma gut hormone concentrations. Acyl ghrelin was not clearly associated with colorectal cancer risk (multivariable OR per 1 SD increase: 1.11; 95% CI, 1.00-1.23). Positive associations were observed for specific subtypes, in particular BRAF-mutated colorectal cancer and right-sided colon cancer, although with nonsignificant heterogeneity. PYY was not related to colorectal cancer risk (multivariable OR per 1 SD: 1.04; 95% CI, 0.95-1.14) or any tumor subtype. In the control participants, ghrelin was inversely correlated with BMI, and PYY was positively correlated with C-peptide and insulin levels. These findings provide limited support for a possible role for ghrelin in colorectal cancer development, primarily in specific anatomical and molecular tumor subtypes. PREVENTION RELEVANCE: The findings of this study do not support a major role for the metabolic gut hormones ghrelin and PYY in colorectal cancer development but suggest the possibility of an involvement for ghrelin in specific tumor subtypes. Elucidating subtype-specific risk factors and mechanisms of carcinogenesis may have implications for precision prevention.

C-reactive Protein and Future Risk of Clinical and Molecular Subtypes of Colorectal Cancer.

BACKGROUND: Inflammation has been implicated in colorectal cancer etiology, but the relationship between C-reactive protein (CRP) and colorectal cancer risk is unclear. We aimed to investigate the association between prediagnostic plasma CRP concentrations and the risk of clinical and molecular colorectal cancer subtypes. METHODS: We used prospectively collected samples from 1,010 matched colorectal cancer case-control pairs from two population-based cohorts in Northern Sweden, including 259 with repeated samples. Conditional logistic regression and linear mixed models were used to estimate relative risks of colorectal cancer, including subtypes based on BRAF and KRAS mutations, microsatellite instability status, tumor location, stage, lag time, and (using unconditional logistic regression) body mass index. RESULTS: CRP was not associated with colorectal cancer risk, regardless of clinical or molecular colorectal cancer subtype. For participants with advanced tumors and blood samples <5 years before diagnosis, CRP was associated with higher risk [OR per 1 unit increase in natural logarithm (ln) transformed CRP, 1.32; 95% confidence interval (CI), 1.01-1.73]. CRP levels increased over time, but average time trajectories were similar for cases and controls (P interaction = 0.19). CONCLUSIONS: Our results do not support intertumoral heterogeneity as an explanation for previous inconsistent findings regarding the role of CRP in colorectal cancer etiology. The possible association in the subgroup with advanced tumors and shorter follow-up likely reflects undiagnosed cancer at baseline. IMPACT: Future efforts to establish the putative role of chronic, low-grade inflammation in colorectal cancer development will need to address the complex relationship between systemic inflammatory factors and tumor microenvironment, and might consider larger biomarker panels than CRP alone.

A longitudinal study of prediagnostic metabolic biomarkers and the risk of molecular subtypes of colorectal cancer.

Body fatness increases the risk of colorectal cancer (CRC). Insulin resistance and altered adipokines are potential mechanisms, but previous biomarker studies have been inconsistent. Intertumoral heterogeneity might provide an explanation. We investigated insulin, C-peptide, adiponectin, and leptin in relation to CRC molecular subtypes using a nested case-control design (1010 cases, 1010 matched controls, median 12.3 years from baseline to CRC diagnosis) from the population-based Northern Sweden Health and Disease Study. Repeated samples were available from 518 participants. Risks of CRC and subtypes, defined by tumor BRAF and KRAS mutations and microsatellite instability (MSI) status, were estimated using conditional logistic regression and linear mixed models. Higher C-peptide and lower adiponectin were associated with increased CRC risk (odds ratios per standard deviation increase (95% CI): 1.11 (1.01, 1.23) and 0.91 (0.83, 1.00), respectively), though weakened when adjusted for body mass index. Insulin and leptin were not associated with CRC risk. Within-individual time trajectories were similar in cases and controls, and no subtype-specific relationships were identified (all Pheterogeneity > 0.1). Adiponectin was weakly inversely associated with the risk of KRAS-mutated (P = 0.08) but not BRAF-mutated or KRAS/BRAF-wildtype CRC, consistent with the one previous study. These findings contribute to an increased understanding of the complex role of body size in CRC.

Circulating levels of inflammatory markers and DNA methylation, an analysis of repeated samples from a population based cohort.

DNA methylation in blood may adapt to conditions affecting our health, such as inflammation, and multiple studies have identified differential DNA methylation related to smoking, obesity and various diseases. The purpose of this study was to evaluate previously reported, and explore possible new, associations between levels of inflammatory markers and DNA methylation in blood. We used a well-characterized study population consisting of 127 individuals, all of whom were participants in the population-based Västerbotten Intervention Programme cohort and had provided two blood samples, ten years apart. Levels of CRP and 160 other proteins were measured in plasma, and DNA methylation levels (assessed using the 850K Illumina Infinium MethylationEPIC BeadChip) were measured in white blood cell DNA. Associations between CpG methylation and protein levels were estimated using linear mixed models. In the study we were able to confirm the direction for 85 of 102 previously reported protein-methylation associations. Depicting associations in a network allowed us to identify CpG sites with associations to multiple proteins, and ten CpG sites were each associated with three or more inflammatory markers. Furthermore, two genetic regions included nine additional unreported CpG sites that may represent trans-acting methylation sites. Our study supports a complex interaction between DNA methylation and circulating proteins involved in the inflammatory response. The notion of trans-acting methylation sites affecting, or being affected by, the expression of genes on completely different chromosomes should be taken into account when interpreting results from epigenome-wide association studies.

Long-term stability of the alcohol consumption biomarker phosphatidylethanol in erythrocytes at -80 °C.

Phosphatidylethanol (PEth) is a recently introduced biomarker with high specificity, high sensitivity, and response correlating with alcohol consumption. It has the potential to be a valuable biomarker in population studies on the health effects of alcohol, however its stability in long-term stored blood is not known. We used LC-MS/MS to assess the stability of PEth-16:0/18:1 in blood samples (packed erythrocytes) that were stored between 1 and 19 years at -80 °C in a biobank from a large population survey. The participants answered a life-style questionnaire that included questions on alcohol consumption. For analysis, we selected blood samples from seven homogenous ethanol consumption cohorts collected at intervals from 1997 to 2015. Despite the narrow stated alcohol consumption range, 10-15 g/day, there were large differences in PEth values between individuals in the cohorts, from below the limit of detection of 0.005 µmol/L to 1.40 µmol/L. The median was 0.08 µmol/L. Neither generalized linear modeling, nor principal component analysis revealed a statistically significant association between time of storage and PEth levels. The PEth results indicate that the participants had, on average, under-reported their alcohol consumption several-fold. The findings suggest that PEth in blood has a sufficient long-term stability for use as an alcohol biomarker in prospective case-control studies. Analysis of blood stored in biobanks could significantly improve the validity of assessments exploring the health effects of alcohol.

Metabolic signature of healthy lifestyle and its relation with risk of hepatocellular carcinoma in a large European cohort.

Background: Studies using metabolomic data have identified metabolites from several compound classes that are associated with disease-related lifestyle factors. Objective: In this study, we identified metabolic signatures reflecting lifestyle patterns and related them to the risk of hepatocellular carcinoma (HCC) in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. Design: Within a nested case-control study of 147 incident HCC cases and 147 matched controls, partial least squares (PLS) analysis related 7 modified healthy lifestyle index (HLI) variables (diet, BMI, physical activity, lifetime alcohol, smoking, diabetes, and hepatitis) to 132 targeted serum-measured metabolites and a liver function score. The association between the resulting PLS scores and HCC risk was examined in multivariable conditional logistic regression models, where ORs and 95% CIs were computed. Results: The lifestyle component's PLS score was negatively associated with lifetime alcohol, BMI, smoking, and diabetes, and positively associated with physical activity. Its metabolic counterpart was positively related to the metabolites sphingomyelin (SM) (OH) C14:1, C16:1, and C22:2, and negatively related to glutamate, hexoses, and the diacyl-phosphatidylcholine PC aaC32:1. The lifestyle and metabolomics components were inversely associated with HCC risk, with the ORs for a 1-SD increase in scores equal to 0.53 (95% CI: 0.38, 0.74) and 0.28 (0.18, 0.43), and the associated AUCs equal to 0.64 (0.57, 0.70) and 0.74 (0.69, 0.80), respectively. Conclusions: This study identified a metabolic signature reflecting a healthy lifestyle pattern which was inversely associated with HCC risk. The metabolic profile displayed a stronger association with HCC than did the modified HLI derived from questionnaire data. Measuring a specific panel of metabolites may identify strata of the population at higher risk for HCC and can add substantial discrimination compared with questionnaire data. This trial was registered at clinicaltrials.gov as NCT03356535.

Are Metabolic Signatures Mediating the Relationship between Lifestyle Factors and Hepatocellular Carcinoma Risk? Results from a Nested Case-Control Study in EPIC.

Background: The "meeting-in-the-middle" (MITM) is a principle to identify exposure biomarkers that are also predictors of disease. The MITM statistical framework was applied in a nested case-control study of hepatocellular carcinoma (HCC) within European Prospective Investigation into Cancer and Nutrition (EPIC), where healthy lifestyle index (HLI) variables were related to targeted serum metabolites.Methods: Lifestyle and targeted metabolomic data were available from 147 incident HCC cases and 147 matched controls. Partial least squares analysis related 7 lifestyle variables from a modified HLI to a set of 132 serum-measured metabolites and a liver function score. Mediation analysis evaluated whether metabolic profiles mediated the relationship between each lifestyle exposure and HCC risk.Results: Exposure-related metabolic signatures were identified. Particularly, the body mass index (BMI)-associated metabolic component was positively related to glutamic acid, tyrosine, PC aaC38:3, and liver function score and negatively to lysoPC aC17:0 and aC18:2. The lifetime alcohol-specific signature had negative loadings on sphingomyelins (SM C16:1, C18:1, SM(OH) C14:1, C16:1 and C22:2). Both exposures were associated with increased HCC with total effects (TE) = 1.23 (95% confidence interval = 0.93-1.62) and 1.40 (1.14-1.72), respectively, for BMI and alcohol consumption. Both metabolic signatures mediated the association between BMI and lifetime alcohol consumption and HCC with natural indirect effects, respectively, equal to 1.56 (1.24-1.96) and 1.09 (1.03-1.15), accounting for a proportion mediated of 100% and 24%.Conclusions: In a refined MITM framework, relevant metabolic signatures were identified as mediators in the relationship between lifestyle exposures and HCC risk.Impact: The understanding of the biological basis for the relationship between modifiable exposures and cancer would pave avenues for clinical and public health interventions on metabolic mediators. Cancer Epidemiol Biomarkers Prev; 27(5); 531-40. ©2018 AACR.

Targeted plasma proteomics identifies a novel, robust association between cornulin and Swedish moist snuff.

Lifestyle behaviors are believed to influence the body's inflammatory state. Chronic low-grade inflammation contributes to the development of major non-communicable diseases such as diabetes, cardiovascular disease and cancer. Inflammation may thus be an important link between lifestyle and disease. We evaluated self-reported physical activity, tobacco use and alcohol consumption in relation to plasma levels of 160 validated inflammatory and cancer biomarkers. The study included 138 participants from a population-based cohort, all with repeated sampling of plasma and data ten years apart, allowing consideration of both intra- and inter-individual variation. Of 17 relationships identified, the strongest was an independent, positive association between cornulin (CRNN) and Swedish moist snuff (snus) use. We replicated the finding in a second cohort of 501 individuals, in which a dose-response relationship was also observed. Snus explained approximately one fifth of the variance in CRNN levels in both sample sets (18% and 23%). In conclusion, we identified a novel, independent, dose-dependent association between CRNN and snus use. Further study is warranted, to evaluate the performance of CRNN as a potential snus biomarker. The putative importance of lifestyle behaviors on a wide range of protein biomarkers illustrates the need for more personalized biomarker cut-offs.

Platinum, palladium, rhodium, molybdenum and strontium in blood of urban women in nine countries.

BACKGROUND: There is little reliable information on human exposure to the metals platinum (Pt), palladium (Pd) and rhodium (Rh), despite their use in enormous quantities in catalytic converters for automobile exhaust systems. OBJECTIVES: To evaluate blood concentrations of Pt (B-Pt), Pd (B-Pd) and Rh (B-Rh) in women from six European and three non-European countries, and to identify potentially influential factors. In addition, molybdenum (Mo) and strontium (Sr) were analysed. METHODS: Blood from 248 women aged 47-61 was analysed by high resolution inductively coupled plasma mass spectrometry under strict quality control. RESULTS: The medians were: B-Pt 0.8 (range <0.6-5.2), B-Pd <5 (<5-9.3), B-Rh <0.4 (<0.4-3.6)ng/L and B-Mo 2.0 (0.2-16) and B-Sr 16.6 (3.5-49) µg/L. Two women with highly elevated B-Pt (242 and 60ng/L), previously cancer treated with cis-platinum, were not included in the data analysis. All elements varied geographically (2-3 times) (B-Pd P=0.05; all other elements P<0.001); variations within each area were generally 5-10 times. Traffic was not associated with increased concentrations. CONCLUSIONS: General population blood concentrations of Pt, Pd and Rh are within or below the single digit ng/L range, much lower than in most previous reports. This is probably due to improved analytical performance, allowing for more reliable information at ultra-trace levels. In general, Mo and Sr agreed with previously reported concentrations. All elements showed geographical and inter-individual variations, but no convincing relationships with self-reported traffic intensity were found. Pt from the antineoplastic drug cis-platinum is retained in the body for years.

Cadmium, mercury and lead in the blood of urban women in Croatia, the Czech Republic, Poland, Slovakia, Slovenia, Sweden, China, Ecuador and Morocco.

OBJECTIVES: The aim of the study was to make an international comparison of blood levels of cadmium (B-Cd), lead (B-Pb) and mercury (B-Hg) of women in seven European, and three non-European cities, and to identify determinants. MATERIALS AND METHODS: About 50 women (age: 46-62) from each city were recruited (totally 480) in 2006-2009. Interview and questionnaire data were obtained. Blood samples were analysed in one laboratory to avoid interlaboratory variation. RESULTS: Between the European cities, the B-Pb and B-Cd results vary little (range of geometric means: 13.5-27.0 µg/l and 0.25-0.65 µg/l, respectively); the variation of B-Hg was larger (0.40-1.38 µg/l). Between the non-European cities the results for B-Pb, B-Cd and B-Hg were 19.2-68.0, 0.39-0.99 and 1.01-2.73 µg/l, respectively. Smoking was a statistically significant determinant for B-Cd, while fish and shellfish intakes contributed to B-Hg and B-Pb, amalgam fillings also contributed to B-Hg. CONCLUSIONS: The present results confirm the previous results from children; the exposure to lead and cadmium varies only little between different European cities suggesting that other factors than the living area are more important. The study also confirms the previous findings of higher cadmium and lead levels in some non-European cities. The geographical variation for mercury is significant.

Coat colour and sex identification in horses from Iron Age Sweden.

Domestication of animals and plants marked a turning point in human prehistory. To date archaeology, archaeozoology and genetics have shed light on when and where all of our major livestock species were domesticated. Phenotypic changes associated with domestication have occurred in all farm animals. Coat colour is one of the traits that have been subjected to the strongest human selection throughout history. Here we use genotyping of coat colour SNPs in horses to investigate whether there were any regional differences or preferences for specific colours associated with specific cultural traditions in Iron Age Sweden. We do this by identifying the sex and coat colour of horses sacrificed at Skedemosse, Öland (Sweden) during the Iron Age, as well as in horses from two sites in Uppland, Ultuna and Valsgärde (dated to late Iron Age). We show that bay, black and chestnut colours were all common and two horses with tobiano spotting were found. We also show how the combination of sex identification with genotyping of just a few SNPs underlying the basic coat colours can be used to identify the minimum number of individuals at a site on a higher level than morphological methods alone. Although separated by 500 km and from significantly different archaeological contexts the horses at Skedemosse and Ultuna are quite homogenous when it comes to coat colour phenotypes, indicating that there were no clear geographical variation in coat colouration in Sweden during the late Iron Age and early Viking Age.

Organophosphorus flame retardants and plasticizers in marine and fresh water biota and in human milk.

The levels and relative proportions of 11 organophosphorus flame retardants and plasticizers (OPs), some of which are reportedly toxic to aquatic organisms, were investigated in human breast milk and samples of fish and mussels from Swedish lakes and coastal areas in order to assess spatial differences in environmental exposure and spatial and temporal differences in human exposure. Some of the biota samples were collected at locations with known potential sources of OPs, but most were collected in background locations. Tris-2-chloroisopropyl phosphate (TCPP) and triphenyl phosphate (TPP) dominated in the biota with levels ranging from 170 to 770 ng g(-1) for TCPP in perch and between 21 and 180 ng g(-1) for TPP. In milk samples, TCPP (median 45 ng g(-1)) and tributyl phosphate (median 12 ng g(-1)) were the most frequently occurring OPs. Among samples of fish from background locations, the concentrations and profiles of most OPs were quite similar, indicating that their sources were diffuse. However, in fish from sample locations near known sources, there were marked differences in OP concentrations and profiles. Fish from a stream receiving surface water from Arlanda airport displayed high levels of OPs (10 200 ng g(-1)) that are commonly used in aircraft hydraulic fluids. Fish collected at points 1 or 2 km downstream of sewage treatment plants showed significantly higher levels of tris(2-butoxyethyl) phosphate (TBEP), one of the most typically abundant OP in effluents from such plants. In the milk samples obtained from women in different towns no distinct differences were detected in OP concentrations or profiles. However, the levels of TBEP tended to be higher in milk collected 10 years ago than in milk collected more recently. However, human exposure to OPs through eating fish or to breastfeeding babies seems to be of minor importance in relation to other potential sources, such as indoor dust inhalation and ingestion.