Plasma C-reactive protein, genetic risk score, and risk of common cancers in the Atherosclerosis Risk in Communities study

A predictive role of C-reactive protein in colorectal cancer risk: an updated meta-analysis from 780,985 participants and 11,289 cancer cases

PURPOSE

This meta-analysis is aimed at understanding the potential role of circulating C-reactive protein (CRP) in the prediction of colorectal cancer (CRC) risk and the potential effect of relevant variables, with specific concern to determine the incorporation of CRP into a CRC risk prediction model.

METHODS

Relevant articles on the association between circulating CRP and CRC risk were searched from PubMed, Embase, Web of Science, and Cochrane Database of Systematic Reviews through August 2022. Random-effects models were used to estimate the pooled relative risk (RR) for the highest versus lowest CRP categories. Linear and non-linear trend analyses were conducted to explore the dose-response associations between CRP and CRC risk.

RESULTS

Twenty-three articles including 780,985 participants and 11,289 cancer cases met the selection criteria. The overall result demonstrated a remarkable association between elevated CRP levels and CRC risk (RR, 1.259; 95% CI, 1.060-1.457), but not in dose-response analysis (RR, 1.002 (95% CI, 0.964-1.041) per natural log unit change in CRP). Subgroup analyses indicated a significant difference when grouped by study location, the length of follow-up, and gender composition. No evidence of publication bias was observed.

CONCLUSION

The predictive role of CRP in CRC incidence is limited to colon cancer and a period of 10 years after the initial discovery of CRP elevation. The result did not support the etiological role of CRP in CRC and the inclusion of CRP into the CRC risk prediction model.

Linking Physical Activity to Breast Cancer via Inflammation, Part 2: The Effect of Inflammation on Breast Cancer Risk

This review synthesized and appraised the evidence for an effect of inflammation on breast cancer risk. Systematic searches identified prospective cohort and Mendelian randomization studies relevant to this review. Meta-analysis of 13 biomarkers of inflammation were conducted to appraise the evidence for an effect breast cancer risk; we examined the dose-response of these associations. Risk of bias was evaluated using the ROBINS-E tool and the quality of evidence was appraised with Grading of Recommendations Assessment, Development, and Evaluation. Thirty-four observational studies and three Mendelian randomization studies were included. Meta-analysis suggested that women with the highest levels of C-reactive protein (CRP) had a higher risk of developing breast cancer [risk ratio (RR) = 1.13; 95% confidence interval (CI), 1.01-1.26] compared with women with the lowest levels. Women with highest levels of adipokines, particularly adiponectin (RR = 0.76; 95% CI, 0.61-0.91) had a reduced breast cancer risk, although this finding was not supported by Mendelian randomization analysis. There was little evidence of an effect of cytokines, including TNFα and IL6, on breast cancer risk. The quality of evidence for each biomarker ranged from very low to moderate. Beyond CRP, the published data do not clearly support the role of inflammation in the development of breast cancer.

Hypothesized Explanations for the Observed Lung Cancer Survival Benefit Among Hispanics/Latinos in the United States

Hispanic/Latino ethnicity is associated with improved survival from non-small cell lung cancer compared to that for non-Hispanic Whites even though Hispanics/Latinos are more likely to potentially have inferior access-to-care and experience greater health disparities. To this end, we conducted a literature review to identify possible explanations for this survival benefit, including the role of chronic obstructive pulmonary disease and cardiovascular diseases, genetic variation, cultural influences, and immigration factors. Overall, intermittent smoking patterns, genetic variation, co-morbidities, and cultural influences were all factors likely to partially explain this survival benefit. On the other hand, immigration factors, acculturation, and access-to-care were less likely to support the survival advantage. Future research should analyze relevant Hispanic/Latino subgroups (e.g., Mexican, Puerto Rican, Cuban, Dominican, Central American, South American) and specifically focus on the relationship between Hispanic/Latino ethnicity and different lung cancer subtypes. If the Hispanic/Latino mortality benefit observed in lung cancer truly exists, a better understanding of the underlying mechanism(s) may help extend these benefits to other ethnic and racial groups.

Biomarkers of glucose homeostasis and inflammation with risk of prostate cancer: A case-cohort study

BACKGROUND

Few prospective studies have examined biomarkers of glucose homeostasis or inflammation with prostate cancer risk by tumor stage or grade.

METHODS

We conducted a case-cohort study to examine associations of pre-diagnosis hemoglobin A1c (HbA1c), c-peptide, and c-reactive protein (CRP) with prostate cancer risk overall and stratified by tumor stage and grade. The study included 390 non-aggressive (T1-2, N0, M0 and Gleason score <8) and 313 aggressive cases (T3-4, or N1, or M1, or Gleason score 8-10) diagnosed after blood draw (1998-2001) and up to 2013, and a random sub-cohort of 1,303 cancer-free men at blood draw in the Cancer Prevention Study-II Nutrition Cohort. Prentice-weighted Cox proportional hazards regression models were used to estimate hazards ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

In the multivariable-adjusted model without body mass index (BMI), HbA1c was inversely associated with non-aggressive prostate cancer (HR per unit increase: 0.89, 95% CI: 0.80-1.00, P=0.04). Analyses stratified by tumor stage and grade separately showed that HbA1c was inversely associated with low-grade prostate cancer (HR per unit increase: 0.89, 95% CI: 0.80-1.00) and positively associated with high-grade prostate cancer (HR per unit increase: 1.15, 95% CI: 1.01-1.30). C-peptide and CRP were not associated with prostate cancer overall or by stage or grade.

CONCLUSIONS

The present study suggests that associations of hyperglycemia with prostate cancer may differ by tumor grade and stage.

IMPACT

Future studies need to examine prostate cancer by tumor stage and grade, and to better understand the role of hyperglycemia in prostate cancer progression.

Polygenic risk prediction models for colorectal cancer: a systematic review

BACKGROUND

Risk prediction models incorporating single nucleotide polymorphisms (SNPs) could lead to individualized prevention of colorectal cancer (CRC). However, the added value of incorporating SNPs into models with only traditional risk factors is still not clear. Hence, our primary aim was to summarize literature on risk prediction models including genetic variants for CRC, while our secondary aim was to evaluate the improvement of discriminatory accuracy when adding SNPs to a prediction model with only traditional risk factors.

METHODS

We conducted a systematic review on prediction models incorporating multiple SNPs for CRC risk prediction. We tested whether a significant trend in the increase of Area Under Curve (AUC) according to the number of SNPs could be observed, and estimated the correlation between AUC improvement and number of SNPs. We estimated pooled AUC improvement for SNP-enhanced models compared with non-SNP-enhanced models using random effects meta-analysis, and conducted meta-regression to investigate the association of specific factors with AUC improvement.

RESULTS

We included 33 studies, 78.79% using genetic risk scores to combine genetic data. We found no significant trend in AUC improvement according to the number of SNPs (p for trend = 0.774), and no correlation between the number of SNPs and AUC improvement (p = 0.695). Pooled AUC improvement was 0.040 (95% CI: 0.035, 0.045), and the number of cases in the study and the AUC of the starting model were inversely associated with AUC improvement obtained when adding SNPs to a prediction model. In addition, models constructed in Asian individuals achieved better AUC improvement with the incorporation of SNPs compared with those developed among individuals of European ancestry.

CONCLUSIONS

Though not conclusive, our results provide insights on factors influencing discriminatory accuracy of SNP-enhanced models. Genetic variants might be useful to inform stratified CRC screening in the future, but further research is needed.

Cardiovascular morbidities in postoperative colorectal cancer patients

This retrospective observational study investigated the long-term prevalence of new-onset cardiovascular disease (CVD) and the predictive role of atherosclerotic plaque in the aorta and iliac arteries for CVD in postoperative colorectal cancer (CRC) patients who received surgical treatment between 2014 and 2015. CVD included coronary or cerebrovascular diseases which required treatment and new-onset CVD included peri-and postoperatively diagnosed CVDs or aggravated CVDs that required additional treatment during follow-up. Of the 2,875 patients included in this study, the prevalence of CVD was 8.9% (255/2875) and 141 (4.9%) developed new-onset CVD. Maximum arterial stenosis in the aorta or iliac arteries occurred in 40.8 ± 18.6% of patients with new-onset CVD and 11.6 ± 13.8% of patients without new-onset CVD (p < 0.001). The mean new-onset CVD-free survival time in patients with > 30% and < 30% stenoses were 52.5 [95% confidence intervals (CIs) 50.0-54.9] and 66.5 (95% CIs 66.2-66.8) months, respectively (p < 0.001). The area under the receiver operating characteristic curve of the maximal arterial stenosis for new-onset CVD was 0.911. These results suggest that CRC patients are at risk for developing new-onset CVD, which is associated with reduced survival. Atherosclerotic burden in the aorta or both iliac arteries may help predict future CVD events.

Molecular Biology Networks and Key Gene Regulators for Inflammatory Biomarkers Shared by Breast Cancer Development: Multi-Omics Systems Analysis

As key inflammatory biomarkers C-reactive protein (CRP) and interleukin-6 (IL6) play an important role in the pathogenesis of non-inflammatory diseases, including specific cancers, such as breast cancer (BC). Previous genome-wide association studies (GWASs) have neither explained the large proportion of genetic heritability nor provided comprehensive understanding of the underlying regulatory mechanisms. We adopted an integrative genomic network approach by incorporating our previous GWAS data for CRP and IL6 with multi-omics datasets, such as whole-blood expression quantitative loci, molecular biologic pathways, and gene regulatory networks to capture the full range of genetic functionalities associated with CRP/IL6 and tissue-specific key drivers (KDs) in gene subnetworks. We applied another systematic genomics approach for BC development to detect shared gene sets in enriched subnetworks across BC and CRP/IL6. We detected the topmost significant common pathways across CRP/IL6 (e.g., immune regulatory; chemokines and their receptors; interferon γ, JAK-STAT, and ERBB4 signaling), several of which overlapped with BC pathways. Further, in gene–gene interaction networks enriched by those topmost pathways, we identified KDs—both well-established (e.g., JAK1/2/3, STAT3) and novel (e.g., CXCR3, CD3D, CD3G, STAT6)—in a tissue-specific manner, for mechanisms shared in regulating CRP/IL6 and BC risk. Our study may provide robust, comprehensive insights into the mechanisms of CRP/IL6 regulation and highlight potential novel genetic targets as preventive and therapeutic strategies for associated disorders, such as BC.

Dietary inflammatory index and the risk of non-communicable chronic disease and mortality: an umbrella review of meta-analyses of observational studies

We aimed to perform an umbrella review of systematic reviews and meta-analyses (SRMAs) of observational studies of the association of the dietary inflammatory index (DII) with the risk of non-communicable chronic disease and mortality in the general population. We searched PubMed, Scopus, and ISI Web of Science to November 2020. For each outcome, the summary effect sizes with the corresponding 95%CIs were recalculated using a random-effects model. The certainty of the evidence and the quality of conduct of published SRMAs were rated using the GRADE and ASMTAR 2 tools, respectively. A total of 11 SRMAs of observational studies, reporting pooled effect sizes for 29 outcomes obtain from 60 prospective cohort and 67 case-control studies, were included. Our results demonstrated evidence of moderate certainty for a positive relation between DII and the risk cardiovascular disease, all-cause mortality, and colorectal cancer. Higher DII was also associated with site-specific cancer risk, but for cancers at most sites, existing evidence is derived from case-control studies with the certainty of evidence being rated low or very low. Our findings suggested that adherence to a diet with high inflammatory features might be associated with a higher risk of colorectal cancer, cardiovascular disease, and all-cause mortality.

Association of high-sensitivity C-reactive protein and odds of breast cancer by molecular subtype: analysis of the MEND study

Breast cancer (BC) in Nigeria is characterized by disproportionately aggressive molecular subtypes. C-reactive protein (CRP) is associated with risk and aggressiveness for several types of cancer. We examined the association of high-sensitivity CRP (hsCRP) with odds of BC by molecular subtype among Nigerian women. Among 296 newly diagnosed BC cases and 259 healthy controls, multivariable logistic regression models were used to estimate adjusted odds ratios (aOR) and 95% confidence intervals (CI) for the association between hsCRP and odds of BC overall and by molecular subtype (luminal A, luminal B, HER2-enriched and triple-negative or TNBC). High hsCRP (> 3 mg/L) was observed in 57% of cases and 31% of controls and was associated with 4 times the odds of BC (aOR: 4.43; 95% CI: 2.56, 7.66) after adjusting for socio-demographic, reproductive, and clinical variables. This association persisted regardless of menopausal status and body mass index (BMI) category. High hsCRP was associated with increased odds of TNBC (aOR: 3.32; 95% CI: 1.07, 10.35), luminal A BC (aOR: 4.03; 95% CI: 1.29, 12.64), and HER2-enriched BC (aOR: 6.27; 95% CI: 1.69, 23.25). Future studies are necessary in this population to further evaluate a potential role for CRP as a predictive biomarker for BC.

Genetically determined elevated C-reactive protein associated with primary colorectal cancer risk: Mendelian randomization with lifestyle interactions

Systemic inflammation-related etiologic pathways via inflammatory cytokines in the development of colorectal cancer (CRC) have not been convincingly determined and may be confounded by lifestyle factors or reverse causality. We investigated the genetically predicted C-reactive protein (CRP) phenotype in the potential causal pathway of primary CRC risk in postmenopausal women in a Mendelian randomization (MR) framework. We employed individual-level data of the Women's Health Initiative Database for Genotypes and Phenotypes Study, which consists of 5 genome-wide association (GWA) studies, including 10,142 women, 737 of whom developed primary CRC. We examined 61 GWA single-nucleotide polymorphisms (SNPs) associated with CRP by using weighted/penalized MR weighted-medians and MR gene-environment interactions that allow some relaxation of the strict variable requirements and attenuate the heterogeneous estimates of outlying SNPs. In lifestyle-stratification analyses, genetically determined CRP exhibited its effects on the decreased CRC risk in non-viscerally obese and high-fat diet subgroups. In contrast, genetically driven CRP was associated with an increased risk for CRC in women who smoked ≥ 15 cigarettes/day, with significant interaction of the gene-smoking relationship. Further, a substantially increased risk of CRC induced by CRP was observed in relatively short-term users (< 5 years) of estrogen (E)-only and also longer-term users (5 to > 10 years) of E plus progestin. Our findings may provide novel evidence on immune-related etiologic pathways connected to CRC risk and suggest the possible use of CRP as a CRC-predictive biomarker in women with particular behaviors and CRP marker-informed interventions to reduce CRC risk.

Genetically Predicted C-Reactive Protein Associated With Postmenopausal Breast Cancer Risk: Interrelation With Estrogen and Cancer Molecular Subtypes Using Mendelian Randomization

Background

Immune-related etiologic pathways that influence breast cancer risk are incompletely understood and may be confounded by lifestyles or reverse causality. Using a Mendelian randomization (MR) approach, we investigated the potential causal relationship between genetically elevated C-reactive protein (CRP) concentrations and primary invasive breast cancer risk in postmenopausal women.

Methods

We used individual-level data obtained from 10,179 women, including 537 who developed breast cancer, from the Women’s Health Initiative Database for Genotypes and Phenotypes Study, which consists of five genome-wide association (GWA) studies. We examined 61 GWA single-nucleotide polymorphisms (SNPs) previously associated with CRP. We employed weighted/penalized weighted–medians and MR gene–environment interactions that allow instruments’ invalidity to some extent and attenuate the heterogeneous estimates of outlying SNPs.

Results

In lifestyle-stratification analyses, genetically elevated CRP decreased risk for breast cancer in exogenous estrogen-only, estrogen + progestin, and past oral contraceptive (OC) users, but only among relatively short-term users (<5 years). Estrogen-only users for ≥5 years had more profound CRP-decreased breast cancer risk in dose–response fashion, whereas past OC users for ≥5 years had CRP-increased cancer risk. Also, genetically predicted CRP was strongly associated with increased risk for hormone-receptor positive or human epidermal growth factor receptor-2 negative breast cancer.

Conclusions

Our findings may provide novel evidence on the immune-related molecular pathways linking to breast cancer risk and suggest potential clinical use of CRP to predict the specific cancer subtypes. Our findings suggest potential interventions targeting CRP–inflammatory markers to reduce breast cancer risk.

Pro-inflammatory cytokine polymorphisms and interactions with dietary alcohol and estrogen, risk factors for invasive breast cancer using a post genome-wide analysis for gene-gene and gene-lifestyle interaction

Molecular and genetic immune-related pathways connected to breast cancer and lifestyles in postmenopausal women are not fully characterized. In this study, we explored the role of pro-inflammatory cytokines such as C-reactive protein (CRP) and interleukin-6 (IL-6) in those pathways at the genome-wide level. With single-nucleotide polymorphisms (SNPs) in the biomarkers and lifestyles together, we further constructed risk profiles to improve predictability for breast cancer. Our earlier genome-wide association gene-environment interaction study used large cohort data from the Women's Health Initiative Database for Genotypes and Phenotypes Study and identified 88 SNPs associated with CRP and IL-6. For this study, we added an additional 68 SNPs from previous GWA studies, and together with 48 selected lifestyles, evaluated for the association with breast cancer risk via a 2-stage multimodal random survival forest and generalized multifactor dimensionality reduction methods. Overall and in obesity strata (by body mass index, waist, waist-to-hip ratio, exercise, and dietary fat intake), we identified the most predictive genetic and lifestyle variables. Two SNPs (SALL1 rs10521222 and HLA-DQA1 rs9271608) and lifestyles, including alcohol intake, lifetime cumulative exposure to estrogen, and overall and visceral obesity, are the most common and strongest predictive markers for breast cancer across the analyses. The risk profile that combined those variables presented their synergistic effect on the increased breast cancer risk in a gene-lifestyle dose-dependent manner. Our study may contribute to improved predictability for breast cancer and suggest potential interventions for the women with the risk genotypes and lifestyles to reduce their breast cancer risk.

Chronic inflammation towards cancer incidence: A systematic review and meta-analysis of epidemiological studies

This systematic review and meta-analysis provides epidemiological data on the relationship between chronic inflammation, as measured by inflammatory blood parameters, and cancer incidence. Two independent researchers searched PubMed, Web Of Science and Embase databases until October 2020. In vitro studies, animal studies, studies with chronically-ill subjects or cross-sectional studies were excluded. Quality was assessed with the Newcastle-Ottawa scale. The 59 nested case-control, 6 nested case-cohort and 42 prospective cohort studies considered 119 different inflammatory markers (top three: CRP, fibrinogen and IL6) and 26 cancer types (top five: colorectal, lung, breast, overall and prostate cancer). Nineteen meta-analyses resulted in ten significant positive associations: CRP-breast (OR = 1.23[1.05-1.43];HR = 1.14[1.01-1.28)), CRP-colorectal (OR = 1.34[1.11-1.60]), CRP-lung (HR = 2.03[1.59-2.60]), fibrinogen-lung (OR = 2.56[1.86-3.54]), IL6-lung (OR = 1.41[1.12-1.78]), CRP-ovarian (OR = 1.41[1.10-1.80]), CRP-prostate (HR = 1.09[1.03-1.15]), CRP-overall (HR = 1.35[1.16-1.57]) and fibrinogen-overall (OR = 1.22[1.07-1.39]). Study quality improvements can be done by better verification of inflammatory status (more than one baseline measurement of one parameter), adjusting for important confounders and ensuring long-term follow-up.

The relation between systemic inflammation and incident cancer in patients with stable cardiovascular disease: a cohort study

Aims

Low-grade inflammation, measured by elevated plasma concentrations of high-sensitive C-reactive protein (CRP), is a risk factor for cardiovascular disease (CVD). There is evidence that low-grade inflammation is also related to a higher risk of cancer. The present prospective cohort study evaluates the relation between low-grade systemic inflammation and risk of cancer in patients with stable CVD.

Methods and results

In total, 7178 patients with stable CVD and plasma CRP levels ≤10 mg/L were included. Data were linked to the Dutch national cancer registry. Cox regression models were fitted to study the relation between CRP and incident CVD and cancer. After a median follow-up time of 8.3 years (interquartile range 4.6–12.3) 1072 incident cancer diagnoses were observed. C-reactive protein concentration was related to total cancer [hazard ratio (HR) 1.35; 95% confidence interval (CI) 1.10–1.65] comparing last quintile to first quintile of CRP. Especially lung cancer, independent of histopathological subtype, was related to CRP (HR 3.39; 95% CI 2.02–5.69 comparing last to first quintile of CRP). Incidence of epithelial neoplasms and especially squamous cell neoplasms were related to CRP concentration, irrespective of anatomical location. Sensitivity analyses after excluding patients with a cancer diagnosis within 1, 2, and 5 years of follow-up showed similar results. No effect modification was observed by smoking status or time since smoking cessation (P-values for interaction > 0.05).

Conclusion

Chronic systemic low-grade inflammation, measured by CRP levels ≤10 mg/L, is a risk factor for incident cancer, markedly lung cancer, in patients with stable CVD. The relation between inflammation and incident cancer is seen in former and current smokers and is uncertain in never smokers.

High-sensitivity C-reactive protein, hemoglobin A1c and breast cancer risk: a nested case-control study from Alberta's Tomorrow Project cohort

PURPOSE

Our aim is to examine the associations between high-sensitivity C-reactive protein (hsCRP) and hemoglobin A1c (HbA1c), common biomarkers of inflammation and insulin resistance, respectively, with breast cancer risk, while adjusting for measures of excess body size.

METHODS

We conducted a nested case-control study within the Alberta's Tomorrow Project cohort (Alberta, Canada) including 197 incident breast cancer cases and 394 matched controls. The sample population included both pre- and postmenopausal women. Serum concentrations of hsCRP and HbA1c were measured from blood samples collected at baseline, along with anthropometric measurements, general health and lifestyle data. Conditional logistic regression was used to evaluate associations between hsCRP, HbA1c, and breast cancer risk adjusted for excess body size (body fat percentage) and other risk factors for breast cancer.

RESULTS

Higher concentrations of hsCRP were associated with elevated breast cancer risk (odds ratio [OR] 1.27; 95% confidence interval [95% CI] 1.03-1.55). The observed associations were unchanged with adjustment for body fat percentage. Higher HbA1c concentrations were not significantly associated with an increased breast cancer risk (OR 1.22; 95% CI 0.17-8.75).

CONCLUSION

These data suggest that hsCRP may be associated with elevated breast cancer risk, independent of excess body size. However, elevated concentrations of HbA1c did not appear to increase breast cancer risk in apparently healthy women.

Pro-inflammatory cytokine polymorphisms in ONECUT2 and HNF4A and primary colorectal carcinoma: a post genome-wide gene-lifestyle interaction study

Immune-related molecular and genetic pathways that are connected to colorectal cancer (CRC) and lifestyles in postmenopausal women are incompletely characterized. In this study, we examined the role of pro-inflammatory biomarkers such as C-reactive protein (CRP) and interleukin-6 (IL-6) in those pathways. Through selection of the best predictive single-nucleotide polymorphisms (SNPs) and lifestyles, our goal was to improve the prediction accuracy and ability for CRC risk. Using large cohort data of postmenopausal women from the Women's Health Initiative Database for Genotypes and Phenotypes Study, we previously conducted a genome-wide association (GWA) for a CRP and IL-6 gene-behavioral interaction study. For the present study, we added GWA-SNPs from outside GWA studies, resulting in a total of 152 SNPs. Together with 41 selected lifestyles, we performed a 2-stage multimodal random survival forest analysis with generalized multifactor dimensionality reduction approach to construct CRC risk profiles. Overall and in obesity strata (by body mass index, waist circumference, waist-to-hip ratio, exercise, and dietary fat intake), we identified the best predictive genetic markers in inflammatory cytokines and lifestyles. Across the strata, 2 SNPs (ONECUT2 rs4092465 and HNF4A rs1800961) and 1 lifestyle factor (relatively short-term past use of oral contraceptives) were the most common and strongest predictive markers for CRC risk. The risk profile that combined those variables exhibited synergistically increased risk for CRC; this pattern appeared more strongly in obese and inactive subgroups. Our results may contribute to improved predictability for CRC and suggest genetically targeted lifestyle interventions for women carrying the inflammatory-risk genotypes, reducing CRC risk.

Inflammatory Biomarkers and Breast Cancer Risk: A Systematic Review of the Evidence and Future Potential for Intervention Research

Measuring systemic chronic inflammatory markers in the blood may be one way of understanding the role of inflammation in breast cancer risk, and might provide an intermediate outcome marker in prevention studies. Here, we present the results of a systematic review of prospective epidemiologic studies that examined associations between systemic inflammatory biomarkers measured in blood and breast cancer risk. From 1 January 2014 to 20 April 2020, we identified 18 unique studies (from 16 publications) that examined the association of systemic inflammatory biomarkers measured in blood with breast cancer risk using prospectively collected epidemiologic data. Only one marker, C-reactive protein, was studied extensively (measured in 13 of the 16 publications), and had some evidence of a positive association with breast cancer risk. Evidence associating other inflammatory biomarkers and more comprehensive panels of markers with the development of breast cancer is limited. Future prospective evidence from expanded panels of systemic blood inflammatory biomarkers is needed to establish strong and independent links with breast cancer risk, along with mechanistic studies to understand inflammatory pathways and demonstrate how breast tissue responds to chronic inflammation. This knowledge could ultimately support the development and evaluation of mechanistically driven interventions to reduce inflammation and prevent breast cancer.

Nutritional genomics, inflammation and obesity

The Human Genome Project has significantly broadened our understanding of the molecular aspects regulating the homeostasis and the pathophysiology of different clinical conditions. Consequently, the field of nutrition has been strongly influenced by such improvements in knowledge - especially for determining how nutrients act at the molecular level in different conditions, such as obesity, type 2 diabetes, cardiovascular disease, and cancer. In this manner, characterizing how the genome influences the diet and vice-versa provides insights about the molecular mechanisms involved in chronic inflammation-related diseases. Therefore, the present review aims to discuss the potential application of Nutritional Genomics to modulate obesity-related inflammatory responses. Arch Endocrinol Metab. 2020;64(3):205-22.

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.

The systemic inflammatory response as a source of biomarkers and therapeutic targets in hepatocellular carcinoma

The pathogenesis of hepatocellular carcinoma (HCC) strongly relates to inflammation, with chronic up-regulation of pro-inflammatory mediators standing as a potential unifying mechanism that underscores the origin and progression of HCC independent of aetiology. Activation of the diverse pro-inflammatory mediators either within the tumour or its microenvironment is part of an active cross-talk between the progressive HCC and the host, which is known to influence clinical outcomes including recurrence after radical treatments and long-term survival. A number of clinical biomarkers to measure the severity of cancer-related inflammation are now available, most of which emerge from routine blood parameters including neutrophil, lymphocyte, platelet counts, as well as albuminaemia and C-reactive protein levels. In this review, we summarise the body of evidence supporting the biologic qualification of inflammation-based scores in HCC and review their potential in facilitating the prognostic assessment and treatment allocation in the individual patient. We also discuss the evidence to suggest modulation of tumour-promoting inflammation may act as a source of novel therapeutic strategies in liver cancer.

Genetic analysis of hsCRP in American Indians: The Strong Heart Family Study

Background

Increased serum levels of C-reactive protein (CRP), an important component of the innate immune response, are associated with increased risk of cardiovascular disease (CVD). Multiple single nucleotide polymorphisms (SNP) have been identified which are associated with CRP levels, and Mendelian randomization studies have shown a positive association between SNPs increasing CRP expression and risk of colon cancer (but thus far not CVD). The effects of individual genetic variants often interact with the genetic background of a population and hence we sought to resolve the genetic determinants of serum CRP in a number of American Indian populations.

Methods

The Strong Heart Family Study (SHFS) has serum CRP measurements from 2428 tribal members, recruited as large families from three regions of the United States. Microsatellite markers and MetaboChip defined SNP genotypes were incorporated into variance components, decomposition-based linkage and association analyses.

Results

CRP levels exhibited significant heritability (h² = 0.33 ± 0.05, p<1.3 X 10⁻²⁰). A locus on chromosome (chr) 6, near marker D6S281 (approximately at 169.6 Mb, GRCh38/hg38) showed suggestive linkage (LOD = 1.9) to CRP levels. No individual SNPs were found associated with CRP levels after Bonferroni adjustment for multiple testing (threshold <7.77 x 10⁻⁷), however, we found nominal associations, many of which replicate previous findings at the CRP, HNF1A and 7 other loci. In addition, we report association of 46 SNPs located at 7 novel loci on chromosomes 2, 5, 6(2 loci), 9, 10 and 17, with an average of 15.3 Kb between SNPs and all with p-values less than 7.2 X 10⁻⁴.

Conclusion

In agreement with evidence from other populations, these data show CRP serum levels are under considerable genetic influence; and include loci, such as near CRP and other genes, that replicate results from other ethnic groups. These findings also suggest possible novel loci on chr 6 and other chromosomes that warrant further investigation.

Mendelian randomization analysis of C-reactive protein on colorectal cancer risk

BACKGROUND

Chronic inflammation is a risk factor for colorectal cancer (CRC). Circulating C-reactive protein (CRP) is also moderately associated with CRC risk. However, observational studies are susceptible to unmeasured confounding or reverse causality. Using genetic risk variants as instrumental variables, we investigated the causal relationship between genetically elevated CRP concentration and CRC risk, using a Mendelian randomization approach.

METHODS

Individual-level data from 30 480 CRC cases and 22 844 controls from 33 participating studies in three international consortia were used: the Genetics and Epidemiology of Colorectal Cancer Consortium (GECCO), the Colorectal Transdisciplinary Study (CORECT) and the Colon Cancer Family Registry (CCFR). As instrumental variables, we included 19 single nucleotide polymorphisms (SNPs) previously associated with CRP concentration. The SNP-CRC associations were estimated using a logistic regression model adjusted for age, sex, principal components and genotyping phases. An inverse-variance weighted method was applied to estimate the causal effect of CRP on CRC risk.

RESULTS

Among the 19 CRP-associated SNPs, rs1260326 and rs6734238 were significantly associated with CRC risk (P = 7.5 × 10-4, and P = 0.003, respectively). A genetically predicted one-unit increase in the log-transformed CRP concentrations (mg/l) was not associated with increased risk of CRC [odds ratio (OR) = 1.04; 95% confidence interval (CI): 0.97, 1.12; P = 0.256). No evidence of association was observed in subgroup analyses stratified by other risk factors.

CONCLUSIONS

In spite of adequate statistical power to detect moderate association, we found genetically elevated CRP concentration was not associated with increased risk of CRC among individuals of European ancestry. Our findings suggested that circulating CRP is unlikely to be a causal factor in CRC development.

Diagnosis of obesity and use of obesity biomarkers in science and clinical medicine

The global epidemic of obesity is a major public health problem today. Obesity increases the risk of many chronic diseases, such as type 2 diabetes, coronary heart disease, and certain types of cancer, and is associated with lower life expectancy. The body mass index (BMI), which is currently used to classify obesity, is only an imperfect measure of abnormal or excessive body fat accumulation. Studies have shown that waist circumference as a measure of fat distribution may improve disease prediction. More elaborate techniques such as magnetic resonance imaging are increasingly available to assess body fat distribution, but these measures are not readily available in routine clinical practice, and health-relevant cut-offs not yet been established. The measurement of biomarkers that reflect the underlying biological mechanisms for the increased disease risk may be an alternative approach to characterize the relevant obesity phenotype. The insulin/insulin-like growth factor (IGF) axis and chronic low-grade inflammation have been identified as major pathways. In addition, specific adipokines such as leptin, adiponectin and resistin have been related to obesity-associated health outcomes. This biomarker research, which is currently further developed with the application of high throughput methods, gives important insights in obesity-related disease etiology and pathophysiological pathways and may be used to better characterize obese persons at high risk of disease development and target disease-causing biomarkers in personalized prevention strategies.

Association of Hospitalization, Critical Illness, and Infection with Brain Structure in Older Adults

OBJECTIVES

To examine the association between hospitalization, critical illness, and infection occurring during middle- and late-life and structural brain abnormalities in older adults.

DESIGN

Prospective cohort study.

SETTING

Atherosclerosis Risk in Communities (ARIC) Study.

PARTICIPANTS

A community sample of adults who were 44 to 66 years of age at study baseline.

MEASUREMENTS

Active surveillance of local hospitals and annual participant contact were used to gather hospitalization information (including International Classification of Diseases, Ninth Revision, codes) on all participants over a 24-year surveillance period. Subsequently, a subset of participants underwent 3-Tesla brain magnetic resonance imaging (MRI) to quantify total and regional brain volumes, white matter hyperintensity (WMH) volume, and white matter microstructural integrity (fractional anisotropy (FA) and mean diffusivity (MD) as measured using diffusion tensor imaging (DTI)).

RESULTS

Of the 1,689 participants included (mean age at MRI 76±5), 72% were hospitalized, 14% had a major infection, and 4% had a critical illness during the surveillance period. Using covariate-adjusted regression, hospitalization was associated with 0.12-standard deviation (SD) greater WMH volume (95% confidence interval (CI)=0.00-0.24) and poorer white matter microstructural integrity (0.17-SD lower FA, 95% CI=-0.27 to -0.06; 0.16-SD greater MD, 95% CI=0.07-0.25) than no hospitalization. There was a dose-dependent relationship between number of hospitalizations, smaller brain volumes, and lower white matter integrity (p-trends ≤.048). In hospitalized participants, critical illness was associated with smaller Alzheimer's disease (AD) signature region (-1.64 cm³ , 95% CI=-3.16 to -0.12); major infection was associated with smaller AD signature region (-1.28 cm³ , 95% CI=-2.21 to -0.35) and larger ventricular volume (3.79 cm³ , 95% CI= 0.81-6.77).

CONCLUSIONS

Whereas all-cause hospitalization was primarily associated with lower white matter integrity, critical illness and major infection were associated with smaller brain volume, particularly within regions implicated in AD.

Enhancing the Infrastructure of the Atherosclerosis Risk in Communities (ARIC) Study for Cancer Epidemiology Research: ARIC Cancer

Background: We describe the expansion of the Atherosclerosis Risk in Communities (ARIC) Study into a cancer cohort. In 1987 to 1989, ARIC recruited 15,792 participants 45 to 64 years old to be sex (55% female), race (27% black), and geographically diverse. ARIC has exceptional data collected during 6 clinical visits and calls every 6 months, repeated biospecimens, and linkage to Medicare claims data.Methods: We established a Cancer Coordinating Center to implement infrastructure activities, convened a Working Group for data use, leveraged ARIC staff and procedures, and developed protocols. We initiated a cancer-specific participant contact, added questions to existing contacts, obtained permission to collect medical records and tissue, abstracted records, linked with state cancer registries, and adjudicated cases and characterizing data.Results: Through 2012, we ascertained and characterized 4,743 incident invasive, first, and subsequent primary cancers among 4,107 participants and 1,660 cancer-related deaths. We generated a total cancer incidence and mortality analytic case file, and analytic case files for bladder, breast, colorectal, liver, lung, pancreas, and prostate cancer incidence, mortality, and case fatality. Adjudication of multiple data sources improved case records and identified cancers not identified via registries. From 2013 onward, we ascertain cases from self-report coupled with medical records. Additional cancer registry linkages are planned.Conclusions: Compared with starting a new cohort, expanding a cardiovascular cohort into ARIC Cancer was an efficient strategy. Our efforts yielded enhanced case files with 25 years of follow-up.Impact: Now that the cancer infrastructure is established, ARIC is contributing its unique features to modern cancer epidemiology research. Cancer Epidemiol Biomarkers Prev; 27(3); 295-305. ©2017 AACR.

Plasma fatty acids and risk of colon and rectal cancers in the Singapore Chinese Health Study

Fatty acid composition in plasma captures both dietary intake and endogenous synthesis. Prospective analyses of plasma fatty acid composition are needed to establish the role of monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) on risk of developing colorectal cancer. To evaluate associations between plasma fatty acid composition and colon or rectal cancer risk separately, a nested case-control study of 350 colorectal (211 colon and 139 rectal) cancer cases and an equal number of individually matched control subjects was conducted within the Singapore Chinese Health Study, a cohort of 63,257 men and women recruited between 1993 and 1998. Fatty acids in pre-diagnostic plasma were quantified using gas chromatography–tandem mass spectrometry. Conditional odds ratios (ORs) and 95% confidence intervals (CIs) comparing highest to lowest quartiles are presented. For colon cancer, inverse associations were reported with higher essential PUFAs, α-linolenic acid (OR = 0.41; 95% CI: 0.23, 0.73; P_trend = 0.005) and linoleic acid (OR = 0.43; 95% CI: 0.23, 0.82; P_trend = 0.008). Higher desaturase activity in the n-6 PUFA synthesis pathway estimated by the arachidonic:linoleic acid ratio was associated with increased colon cancer risk (OR = 3.53; 95% CI: 1.82, 6.85; P_trend = 0.006), whereas higher desaturase activity in the MUFA synthesis pathway estimated by the oleic:stearic acid ratio was associated with decreased colon cancer risk (OR = 0.42; 95% CI: 0.19, 0.92; P_trend = 0.024). There was no significant association between the essential fatty acids or the desaturase indices and rectal cancer risk. Endogenous synthesis of arachidonic and oleic acids has an impact on colon cancer development.

Higher consumption of “good fats,” or their natural creation by the body, may help protect people from colon cancer. Jian-Min Yuan from the University of Pittsburgh, USA, and colleagues used samples from the Singapore Chinese Health Study to examine fatty acids contained in blood plasma from 350 people who later developed colorectal cancer and an equal number of matched control individuals. They found that higher blood levels—which reflect dietary intake—of the essential polyunsaturated fatty acids linolenic acid and α-linolenic acid were associated with a lower risk of colon cancer. So was oleic acid, a monounsaturated fat created by the body, whereas conversion of linolenic acid to another fatty acid called arachidonic acid boosted colon cancer risk. No effect was seen on rectal cancer risk. Diets rich in linolenic acid may help prevent colon cancer.

Associations of C-Reactive Protein, Granulocytes and Granulocyte-to-Lymphocyte Ratio with Mortality from Breast Cancer in Non-Institutionalized American Women

Inflammation may play a role in breast cancer, but evidence in the general population is lacking. We investigated the association between serum inflammatory markers (C-reactive protein (CRP), absolute granulocyte count (AGC) and granulocyte-to-lymphocyte (G/L) ratio) and breast cancer (BCa) mortality in American women while accounting for adiposity. From the Third National Health and Nutrition Examination Survey (NHANES III) we selected all women aged 20+ without any known history of cancer (n = 7,780). Multivariable Cox regression models were used to assess CRP, AGC and G/L ratio in relation to mortality from BCa, all cancer, cardiovascular disease and all causes. Stratification analyses by body mass index (BMI) and waist circumference were performed to investigate the effect of adiposity on this association. During a mean follow-up of 167 months, 44 women died from BCa. After adjustments for BMI and waist circumference, only G/L ratio was associated to risk of BCa death (e.g. HR: 2.35, 95% CI: 1.36–4.06 for the 3^rd compared to the 1^st tertile, P_trend = 0.01). Except for a borderline interaction between CRP categories and obesity by BMI, no statistically significant interaction between markers and categories of BMI or waist circumference was observed. All three markers were associated with mortality from cardiovascular disease and all causes. Our findings support a role of inflammation in BCa mortality which may involve mechanisms apart from obesity, and potential usefulness of GLR as a marker in assessing inflammation and cancer.

The George W. Comstock Center for Public Health Research and Prevention: A Century of Collaboration, Innovation, and Translation

The Johns Hopkins Bloomberg School of Public Health has been engaged in public health research and practice in Washington County, Maryland, nearly since its inception a century ago. In 2005, the center housing this work was renamed the George W. Comstock Center for Public Health Research and Prevention to honor its pioneering leader. Principles that guided innovation and translation well in the past included: research synergies and opportunities for translation realized through longstanding connection with the community; integration of training with public health research; lifelong learning, mentorship, and teamwork; and efficiency through economies of scale. These principles are useful to consider as we face the challenges of improving the health of the population over the next 100 years.

Sleep duration and risk of lung cancer in the physicians' health study

Background and Objectives

Lung cancer is the most common cancer and cancer related cause of death worldwide. However, the association between sleep duration and incident lung cancer has not been investigated in a prospective cohort study.

Methods

We prospectively examined the association between sleep duration and incident lung cancer in a cohort of 21, 026 United States (US) male physicians. Self-reported sleep duration was ascertained during 2002 annual follow-up questionnaire. Incident lung cancer was ascertained through yearly follow-up questionnaires. Cox regression was used to estimate relative risk of incident lung cancer.

Results

The average age at baseline was 68.3±8.8 yr. During a mean follow up of 7.5 (±2.2) yr, 150 cases of lung cancer occurred. Using 7 h of sleep as the reference group, multivariable adjusted hazard ratios (95%CI) for lung cancer were 1.18 (0.77-1.82), 1.0 (ref), and 0.97 (0.67-1.41) from lowest to the highest category of sleep duration (P for quadratic trend 0.697), respectively. In a secondary analysis, smoking status did not modify the sleep duration-lung cancer association (P=0.78). Tere was no evidence for an interaction between sleep duration and sleep apnea on the risk of lung cancer either (P=0.65).

Conclusions

Our data failed to show a higher risk of lung cancer in association with altered sleep duration among US male physicians.

Increased peri-ductal collagen micro-organization may contribute to raised mammographic density

BACKGROUND

High mammographic density is a therapeutically modifiable risk factor for breast cancer. Although mammographic density is correlated with the relative abundance of collagen-rich fibroglandular tissue, the causative mechanisms, associated structural remodelling and mechanical consequences remain poorly defined. In this study we have developed a new collaborative bedside-to-bench workflow to determine the relationship between mammographic density, collagen abundance and alignment, tissue stiffness and the expression of extracellular matrix organising proteins.

METHODS

Mammographic density was assessed in 22 post-menopausal women (aged 54-66 y). A radiologist and a pathologist identified and excised regions of elevated non-cancerous X-ray density prior to laboratory characterization. Collagen abundance was determined by both Masson's trichrome and Picrosirius red staining (which enhances collagen birefringence when viewed under polarised light). The structural specificity of these collagen visualisation methods was determined by comparing the relative birefringence and ultrastructure (visualised by atomic force microscopy) of unaligned collagen I fibrils in reconstituted gels with the highly aligned collagen fibrils in rat tail tendon. Localised collagen fibril organisation and stiffness was also evaluated in tissue sections by atomic force microscopy/spectroscopy and the abundance of key extracellular proteins was assessed using mass spectrometry.

RESULTS

Mammographic density was positively correlated with the abundance of aligned periductal fibrils rather than with the abundance of amorphous collagen. Compared with matched tissue resected from the breasts of low mammographic density patients, the highly birefringent tissue in mammographically dense breasts was both significantly stiffer and characterised by large (>80 μm long) fibrillar collagen bundles. Subsequent proteomic analyses not only confirmed the absence of collagen fibrosis in high mammographic density tissue, but additionally identified the up-regulation of periostin and collagen XVI (regulators of collagen fibril structure and architecture) as potential mediators of localised mechanical stiffness.

CONCLUSIONS

These preliminary data suggest that remodelling, and hence stiffening, of the existing stromal collagen microarchitecture promotes high mammographic density within the breast. In turn, this aberrant mechanical environment may trigger neoplasia-associated mechanotransduction pathways within the epithelial cell population.

Obesity Biomarkers, Metabolism and Risk of Cancer: An Epidemiological Perspective

Obesity is associated with metabolic alterations that may pose a biological link between body fatness and risk of cancer. Elucidating the role of obesity-related biomarkers in cancer development is essential for developing targeted strategies aiming at obesity-associated cancer prevention. Molecular epidemiological studies of the past decades have provided evidence that major hormonal pathways linking obesity and cancer risk include the insulin and insulin-like growth factor-1 (IGF-1) axis, sex-steroid hormones, adipokines and chronic low-grade inflammation. These pathways are interrelated with each other, and their importance varies by obesity-related cancer type. The insulin/IGF-1 axis has been implicated to play an important mediating role in the association between obesity and risk of pancreatic, colorectal and prostate cancer. Endogenous sex-steroid hormone concentrations, in particular obesity-associated pre-diagnostic elevations of estrogens and androgens, play an important role in postmenopausal breast cancer and endometrial cancer development. The adipokines adiponectin and leptin and adipocyte-mediated chronic low-grade inflammation represented by the acute-phase C-reactive protein may explain a substantial part of the association between obesity and risk of colorectal cancer. There is less evidence on whether these hormonal pathways play a mediating role in other obesity-associated types of cancer. In this chapter, the molecular epidemiologic evidence from prospective studies relating circulating obesity-related biomarkers to cancer risk is summarized, taking into account available evidence from Mendelian Randomization investigations aiming at improving causal inference.

Interleukin-6 and risk of colorectal cancer: results from the CLUE II cohort and a meta-analysis of prospective studies

PURPOSE

The association between prediagnostic interleukin-6 (IL-6) concentrations and risk of colorectal cancer was evaluated in a nested case-control study and a meta-analysis of prospective studies.

METHODS

Colorectal cancer cases (n = 173) and matched controls (n = 345) were identified between 1989 and 2000 among participants in the CLUE II cohort of Washington Country, Maryland. Matched odds ratios and the corresponding 95 % confidence intervals (CIs) were estimated using conditional logistic regression models.

RESULTS

Participants in the highest third of plasma IL-6 concentration had a 2.48 times higher risk of colon cancer compared to participants in the bottom third (95 % CI 1.26-4.87; p-trend 0.02) after multivariate adjustment. This association did not differ according to the stage of disease, age, sex, or other potential modifying variables and remained statistically significant after adjustment for C-reactive protein concentrations. No statistically significant association was observed for rectal cancer risk. The meta-analysis of six prospective studies yielded an increased but borderline statistically significant risk of colon cancer per 1 U increase in naturally logarithm-transformed IL-6 (summary RR 1.22; 95 % CI 1.00-1.49; I (2) 46 %). An inverse association was noted for rectal cancer (RR 0.69; 95 % CI 0.54-0.88; I (2) 0 %), but there was evidence for small-study effects (p 0.02).

CONCLUSION

Our findings provide support for a modest positive association between IL-6 concentrations and colon cancer risk. More work is needed to determine whether IL-6 is a valid marker of colorectal inflammation and whether such inflammation contributes to colon and rectal cancer risk.

Metabolic serum biomarkers for the prediction of cancer: a follow-up of the studies conducted in the Swedish AMORIS study

The Swedish Apolipoprotein MOrtality RISk study (AMORIS) contains information on more than 500 biomarkers collected from 397,443 men and 414,630 women from the greater Stockholm area during the period 1985–1996. Using a ten-digit personal identification code, this database has been linked to Swedish national registries, which provide data on socioeconomic status, vital status, cancer diagnosis, comorbidity, and emigration. Within AMORIS, 18 studies assessing risk of overall and site-specific cancers have been published, utilising a range of serum markers representing glucose and lipid metabolism, immune system, iron metabolism, liver metabolism, and bone metabolism. This review briefly summarises these findings in relation to more recently published studies and provides an overview of where we are today and the challenges of observational studies when studying cancer risk prediction.

Overall, more recent observational studies supported previous findings obtained in AMORIS, although no new results have been reported for serum fructosamine and inorganic phosphate with respect to cancer risk. A drawback of using serum markers in predicting cancer risk is the potential fluctuations following other pathological conditions, resulting in non-specificity and imprecision of associations observed. Utilisation of multiple combination markers may provide more specificity, as well as give us repeated instead of single measurements. Associations with other diseases may also necessitate further analytical strategies addressing effects of serum markers on competing events in addition to cancer. Finally, delineating the role of serum metabolic markers may generate valuable information to complement emerging clinical studies on preventive effects of drugs and supplements targeting metabolic disorders against cancer.

Biomarkers of Inflammation and Immune Function and Risk of Colorectal Cancer

A substantial number of prospective epidemiological studies have been conducted to investigate the association between biomarkers of inflammation and immune function and risk of colorectal cancer. Although pre-diagnostic concentrations of these biomarkers, especially C-reactive protein, have been associated with a higher risk of colorectal cancer in some studies, this association does not seem to have a robust support without hints of bias. Future prospective studies should evaluate multiple inflammatory biomarkers with longitudinal measures over the follow-up taking advantage of new multiplex cytokine quantification arrays and use more sophisticated joint or biomarker pattern statistical approaches to capture the complex and dynamic interplay between biomarkers and risk of colorectal cancer. Large collaborative consortia and Mendelian randomization studies should be encouraged to diminish the threat of biases and improve the reliability of this literature.

Prediagnostic serum inflammatory markers in relation to breast cancer risk, severity at diagnosis and survival in breast cancer patients

Inflammation has been linked to cancer but its role in breast cancer is unclear. We investigated common serum markers of inflammation: C-reactive protein (CRP), albumin, haptoglobin and white blood cells (WBC) in relation to breast cancer incidence, severity and survival. A total of 155179 women aged 20 and older without any history of cancer were selected from a large Swedish cohort. Hazard ratios (HRs) for breast cancer were estimated with Cox regression, adjusting for potential confounders. Ordered and binomial logistic regression models were used to assess the associations of serum inflammatory markers with breast cancer severity and oestrogen receptor (ER) positivity at diagnosis, on the other. Cumulative incidence functions by levels of inflammatory markers were assessed for early death from breast cancer and all causes. During a mean follow-up of 18.3 years, 6606 women were diagnosed with breast cancer, of whom 1474 died. A positive association with incident breast cancer was seen for haptoglobin ≥ 1.4g/l [HR 1.09; 95% confidence interval (CI): 1.00-1.18] compared to lower levels. No association was observed between inflammatory markers and breast cancer severity or ER positivity. Higher haptoglobin was linked to risk of early death from breast cancer (HR: 1.27, 95% CI: 1.02-1.59), whereas higher risk of early death from all causes was additionally found with CRP ≥ 10mg/l (HR: 1.19, 95% CI: 1.04-1.36) and WBC ≥ 10×10(9)/l (HR: 1.57, 1.14-2.16). Our findings indicate that prediagnostic serum inflammatory markers were weakly linked to incident breast cancer but corresponded to worse survival after diagnosis.

C-reactive protein and risk of breast cancer: A systematic review and meta-analysis

Associations between elevated C-reactive protein (CRP) and breast cancer risk have been reported for many years, but the results remain controversial. To address this issue, a meta-analysis was therefore conducted. Eligible studies were identified by searching the PubMed and EMBASE up to December 2014. Study-specific risk estimates were combined using a random-effects model. Altogether fifteen cohort and case-control studies were included in this meta-analysis, involving a total of 5,286 breast cancer cases. The combined OR per natural log unit change in CRP for breast cancer was 1.16 (95% CI: 1.06-1.27). There was moderate heterogeneity among studies (I(2) = 45.9%). The association was stronger in Asian population (OR = 1.57, 95% CI: 1.25-1.96) compared to European (OR = 1.12, 95% CI: 1.02-1.23) and American (OR = 1.08, 95% CI: 1.01-1.16). Prediagnostic high-sensitivity CRP concentrations (OR = 1.22, 95% CI: 1.10-1.35) was superior to common CRP (OR = 1.08, 95% CI: 1.01-1.15) in predicting breast cancer risk. The meta-analysis indicated that elevated CRP levels was associated with increased risk of breast cancer. Further research effort should be performed to identify whether CRP, as a marker of inflammation, plays a direct role in breast carcinogenesis.

Plasma C-reactive protein and risk of breast cancer in two prospective studies and a meta-analysis

BACKGROUND

C-reactive protein (CRP) has been evaluated as a risk factor for breast cancer in epidemiologic studies. However, results from prospective studies are inconsistent.

METHODS

We evaluated the association using prediagnostic blood samples in a case-control study nested within the Nurses' Health Study (NHS) and the full cohort of the Women's Health Study (WHS). A total of 943 cases in the NHS and 1,919 cases in the WHS contributed to the analysis. Conditional logistic regression and Cox proportional hazards model were used in the NHS and WHS, respectively. We pooled our results with prior prospective studies using random effect meta-analysis.

RESULTS

In the NHS, higher CRP levels were associated with a suggestively increased risk of breast cancer [quintile 5 vs. 1: relative risk (RR), 1.27; 95% confidence interval (CI), 0.93-1.73; Ptrend = 0.02]; results did not vary significantly by tumor invasiveness or hormone receptor status. However, no association was observed in the WHS for overall risk (quintile 5 vs. 1: RR, 0.89; 95% CI, 0.76-1.06; Ptrend = 0.38) or by tumor invasiveness or hormone receptor status. The meta-analysis (including 5,371 cases from 11 studies) showed a modestly increased risk among women in the highest versus lowest categories of CRP (RR, 1.26; 95% CI, 1.07-1.49).

CONCLUSIONS

Existing data from prospective studies suggest that CRP, a nonspecific marker of inflammation, is modestly positively associated with breast cancer risk.

IMPACT

Our findings provide support to the concept that inflammation can influence breast cancer development.

Mendelian Randomization: New Applications in the Coming Age of Hypothesis-Free Causality

Mendelian randomization (MR) is an approach that uses genetic variants associated with a modifiable exposure or biological intermediate to estimate the causal relationship between these variables and a medically relevant outcome. Although it was initially developed to examine the relationship between modifiable exposures/biomarkers and disease, its use has expanded to encompass applications in molecular epidemiology, systems biology, pharmacogenomics, and many other areas. The purpose of this review is to introduce MR, the principles behind the approach, and its limitations. We consider some of the new applications of the methodology, including informing drug development, and comment on some promising extensions, including two-step, two-sample, and bidirectional MR. We show how these new methods can be combined to efficiently examine causality in complex biological networks and provide a new framework to data mine high-dimensional studies as we transition into the age of hypothesis-free causality.

Association between high-sensitivity C-reactive protein (hsCRP) and change in mammographic density over time in the SWAN mammographic density subcohort

PURPOSE

High mammographic density (MD) is a strong risk factor for breast cancer. Chronic inflammation may be related to breast cancer risk through a mechanism involving the percent of breast area that is dense (percent MD). Longitudinal assessments, however, are lacking and thus were constructed to evaluate the relationship between chronic inflammation and percent MD.

METHODS

We evaluated whether elevated (>3 mg/L) high-sensitivity C-reactive protein (hsCRP), a biomarker of inflammation, was associated with change in percent MD among 653 women aged 42-52 years at baseline in the Study of Women's Health Across the Nation, a longitudinal study of midlife women. We used a mixed model to analyze data from an average of 4.7 mammograms per woman collected during an average follow-up of 4.9 years (SD = 1.47).

RESULTS

Elevated hsCRP at baseline was associated with lower baseline percent MD and a significantly slower annual decline over time of percent MD in an adjusted model that did not include body mass index (BMI) (β = 0.88, 95 % CI 0.44, 1.31). This association was attenuated and nonsignificant when BMI was included in the model (β = 0.37, 95 % CI -0.09, 0.84). Elevated hsCRP levels over time (time-varying elevated hsCRP levels) were also associated with a significantly slower decline in percent MD (β = 0.62, 95 % CI 0.30, 0.94). This association was attenuated, but still significant after adjusting for baseline BMI (β = 0.40, 95 % CI 0.07, 0.73).

CONCLUSION

These results suggest that inflammation may be related to slower reduction in percent MD.

A prospective follow-up study of the relationship between C-reactive protein and human cancer risk in the Chinese Kailuan Female Cohort

BACKGROUND

C-reactive protein (CRP) has been associated with cancer risk in some prospective studies. However, the associations have not been entirely consistent and have not been evaluated in Chinese females. We conducted a large population-based cohort study to investigate whether elevated levels of CRP at baseline are associated with an increased risk of cancer among Chinese females.

METHODS

A total of 19,437 women from the Chinese Kailuan Female Cohort were enrolled in the study in July 2006. Levels of high-sensitivity CRP (hsCRP) were tested at baseline for all subjects. Multivariable Cox proportional hazards regression models were used to evaluate the association between levels of hsCRP and risk of all cancers, including breast cancer, lung cancer, colorectal cancer, and other cancers.

RESULTS

By December 31, 2011, a total of 322 incident cancer cases accrued. Compared with women with lower hsCRP levels (<1 mg/L), women with higher hsCRP (>3 mg/L) had a significantly increased risk of all incident cancers [HR, 1.62; 95% confidence intervals (CI), 1.23-2.14; P(trend) = 0.001] and breast cancer (HR, 1.74; 95% CI, 1.01-2.97; P(trend) = 0.047). The significant association between hsCRP levels and breast cancer risk was apparent among younger women (<50 years; HR, 2.76; 95% CI, 1.18-6.48).

CONCLUSION

Elevated levels of hsCRP at baseline may be associated with an increased risk of cancer, especially breast cancer, and particularly in younger Chinese women.

IMPACT

Our findings provide additional evidence for a role of inflammation in carcinogenesis and suggest that CRP may be a potentially useful biomarker of cancer risk in this population.

Associations between ALOX, COX, and CRP polymorphisms and breast cancer among Hispanic and non-Hispanic white women: The breast cancer health disparities study

Chronic inflammation is suggested to be associated with specific cancer sites, including breast cancer. Recent research has focused on the roles of genes involved in the leukotriene/lipoxygenase and prostaglandin/cyclooxygenase pathways in breast cancer etiology. We hypothesized that genes in ALOX/COX pathways and CRP polymorphisms would be associated with breast cancer risk and mortality in our sample of Hispanic/Native American (NA) (1430 cases, 1599 controls) and non-Hispanic white (NHW) (2093 cases, 2610 controls) women. A total of 104 Ancestral Informative Markers was used to distinguish European and NA ancestry. The adaptive rank truncated product (ARTP) method was used to determine the significance of associations for each gene and the inflammation pathway with breast cancer risk and by NA ancestry. Overall, the pathway was associated with breast cancer risk (PARTP = 0.01). Two-way interactions with NA ancestry (P(adj)  < 0.05) were observed for ALOX12 (rs2292350, rs2271316) and PTGS1 (rs10306194). We observed increases in breast cancer risk in stratified analyses by tertiles of polyunsaturated fat intake for ALOX12 polymorphisms; the largest increase in risk was among women in the highest tertile with ALOX12 rs9904779CC (Odds Ratio (OR), 1.49; 95% Confidence Interval (CI) 1.14-1.94, P(adj) = 0.01). In a sub-analysis stratified by NSAIDs use, two-way interactions with NSAIDs use were found for ALOX12 rs9904779 (P(adj)  = 0.02), rs434473 (P(adj ) = 0.02), and rs1126667 (P(adj)  =  0.01); ORs for ALOX12 polymorphisms ranged from 1.55 to 1.64 among regular users. Associations were not observed with breast cancer mortality. These findings could support advances in the discovery of new pathways related to inflammation for breast cancer treatment.

C-reactive protein, interleukin-6 and the risk of colorectal cancer: a meta-analysis

PURPOSE

Many studies have evaluated the associations between pre-diagnostic circulating C-reactive protein (CRP), interleukin-6 (IL-6) and colorectal cancer risk, but their results are inconsistent. We therefore conducted a meta-analysis to investigate these associations.

METHODS

A comprehensive literature search up to October 2013 was undertaken in PubMed. Pooled relative risk (RR) estimates and 95% confidence intervals (CIs) were used to calculate estimated effect.

RESULTS

Eighteen studies on CRP comprising a total of 4,706 colorectal cancer cases were included in this meta-analysis. The summary RR of colorectal cancer for one unit change in natural logarithm (ln) CRP was 1.12 [95% CI (1.05-1.21)]. There was statistically significant heterogeneity among studies (p = 0.006; I (2) = 51.7%). After excluding the studies contributing most to the heterogeneity, summary estimate was essentially unchanged. In addition, the association was significant for colon cancer [RR = 1.13, 95 % CI (1.05-1.21)], not for rectal cancer [RR = 1.03, 95% CI (0.90-1.17)]. We also found that CRP was significantly associated with increased risk of colorectal cancer among men, but not among women. There were six studies on IL-6 that involved a total of 1,068 colorectal cancer cases. The pooled RR of colorectal cancer for one unit change in ln IL-6 was 1.10 (95% CI 0.88-1.36), and no statistically significant heterogeneity was found (p = 0.175; I(2) = 34.8%).

CONCLUSION

Our results suggest that pre-diagnostic circulating CRP is associated with increased risk of colorectal cancer. However, there is no significant association between IL-6 and colorectal cancer risk.