Genetic variation in C-reactive protein in relation to colon and rectal cancer risk and survival

C-Reactive Protein Is Not the Driver Factor in Ulcerative Colitis

Purpose: C-reactive protein (CRP) functions as a nonspecific marker in various inflammatory disorders, particularly in evaluating the efficacy of pharmacological treatments in patients with ulcerative colitis. The existing body of evidence does not offer adequate support for the direct implication of CRP in modulating the advancement of ulcerative colitis. Methods: Our study employed a rigorous mouse model. An ulcerative colitis mouse model was established by subjecting CRP-deficient mice to dextran sulfate sodium (DSS) treatment. The phenotype of the mice, which encompassed parameters such as body weight, colon length, and spleen weight, was meticulously evaluated. Additionally, various physiological and biochemical indicators were assessed, including colon histopathology, expression levels of inflammatory factors, and staining of the intestinal mucus layer. Results: The absence of CRP did not significantly affect the phenotype, physiological characteristics, and biochemical indices in a mouse model of ulcerative colitis compared to mice with wild-type CRP. Additionally, eliminating intestinal bacteria flora interference through antibiotic treatment revealed that mice lacking CRP did not demonstrate any notable variations in the ulcerative colitis model. Meanwhile, the survival rate of mice lacking CRP did not exhibit a statistically significant difference compared to wild-type mice. Conclusion: The results of our study suggest that CRP may not directly mediate ulcerative colitis. Instead, it is more likely to be a bystander that is present alongside with elevated inflammatory factors. Further investigation is warranted to determine the precise role of CRP in humans, given the significant limitations associated with the use of mouse models.

The death rate of COVID-19 infection in different SARS-CoV-2 variants was related to C-reactive protein gene polymorphisms

The serum level of C-reactive protein (CRP) is a significant independent risk factor for Coronavirus disease 2019 (COVID-19). A link was found between serum CRP and genetic diversity within the CRP gene in earlier research. This study examined whether CRP rs1205 and rs1800947 polymorphisms were associated with COVID-19 mortality among various severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) variants. We genotyped CRP rs1205 and rs1800947 polymorphisms in 2023 deceased and 2307 recovered patients using the polymerase chain reaction-restriction fragment length polymorphism method. There was a significant difference between the recovered and the deceased patients in terms of the minor allele frequency of CRP rs1205 T and rs1800947 G. In all three variants, COVID-19 mortality rates were associated with CRP rs1800947 GG genotype. Furthermore, CRP rs1205 CC and rs1800947 GG genotypes showed higher CRP levels. It was found that the G-T haplotype was prevalent in all SARS-CoV-2 variants. The C-C and C-T haplotypes were statistically significant in Delta and Omicron BA.5 variants, respectively. In conclusion, polymorphisms within the CRP gene may relate to serum CRP levels and mortality among COVID-19 patients. In order to verify the utility of CRP polymorphism correlation in predicting COVID-19 mortality, a replication of these results is needed.

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.

Pre-diagnostic C-reactive protein concentrations, CRP genetic variation and mortality among individuals with colorectal cancer in Western European populations

BACKGROUND

The role of elevated pre-diagnostic C-reactive protein (CRP) concentrations on mortality in individuals with colorectal cancer (CRC) remains unclear.

METHODS

We investigated the association between pre-diagnostic high-sensitivity CRP concentrations and CRP genetic variation associated with circulating CRP and CRC-specific and all-cause mortality based on data from 1,235 individuals with CRC within the European Prospective Investigation into Cancer and Nutrition cohort using multivariable-adjusted Cox proportional hazards regression.

RESULTS

During a median follow-up of 9.3 years, 455 CRC-specific deaths were recorded, out of 590 deaths from all causes. Pre-diagnostic CRP concentrations were not associated with CRC-specific (hazard ratio, HR highest versus lowest quintile 0.92, 95% confidence interval, CI 0.66, 1.28) or all-cause mortality (HR 0.91, 95% CI 0.68, 1.21). Genetic predisposition to higher CRP (weighted score based on alleles of four CRP SNPs associated with higher circulating CRP) was not significantly associated with CRC-specific mortality (HR per CRP-score unit 0.95, 95% CI 0.86, 1.05) or all-cause mortality (HR 0.98, 95% CI 0.90, 1.07). Among four investigated CRP genetic variants, only SNP rs1205 was significantly associated with CRC-specific (comparing the CT and CC genotypes with TT genotype, HR 0.54, 95% CI 0.35, 0.83 and HR 0.58, 95% CI 0.38, 0.88, respectively) and all-cause mortality (HR 0.58, 95% CI 0.40, 0.85 and 0.64, 95% CI 0.44, 0.92, respectively).

CONCLUSIONS

The results of this prospective cohort study do not support a role of pre-diagnostic CRP concentrations on mortality in individuals with CRC. The observed associations with rs1205 deserve further scientific attention.

High Neutrophil-To-Lymphocyte Ratio (NLR) and Systemic Immune-Inflammation Index (SII) Are Markers of Longer Survival After Metastasectomy of Patients With Liver-Only Metastasis of Rectal Cancer

Background: The literature data regarding colon cancer patients with liver-only metastases (CLM) show that NLR determined before metastasectomy is a prognostic marker of shorter relapse-free survival (RFS), but no results has been reported to date for rectal cancer patients with liver-only metastases (RLM). This study aimed to investigate the NLR and SII in CLM and RLM.

Methods: Relapse-free (RFS) and overall survival (OS) were evaluated in 67 CLM and 103 RLM patients with a median follow-up of 46.5 and 59.8 months, respectively. Pre- and/or postoperative chemotherapy ± targeted treatment was applied in 96% and 87% of CLM and RLM patients, respectively. The cut-off level for hematologic parameters were determined by receiver operating characteristic (ROC) analysis. Univariate analysis was performed by Kaplan-Meier method and log rank test. For multivariate analysis Cox regression was applied.

Results: In univariate analysis low NLR (cut-off 2) and SII (535) were predictors of longer RFS in case of CLM (p < 0.01). In contrast, for RLM high NLR (2.42) and SII (792) were predictors of longer RFS (p < 0.001). For RLM both NLR and SII proved to be independent markers of RFS (HR 0.66 (95% CI 0.52–0.84) and 0.73 (0.57–0.91), respectively) and OS (0.76 (0.58–0.99) and 0.66 (0.5–0.87), respectively). Only NLR (1.44 (1.04–1.99)) was independent marker of RFS for CLM. The preoperative treatment has not influenced the role of NLR or SII.

Conclusion: In contrast to CLM, in RLM the high NLR or SII determined before metastasectomy proved to be independent prognostic factors of longer RFS and OS.

Genetic variants associated with circulating C-reactive protein levels and colorectal cancer survival: Sex-specific and lifestyle factors specific associations

Elevated blood levels of C-reactive protein (CRP) have been linked to colorectal cancer (CRC) survival. We evaluated genetic variants associated with CRP levels and their interactions with sex and lifestyle factors in association with CRC-specific mortality. Our study included 16 142 CRC cases from the International Survival Analysis in Colorectal Cancer Consortium. We identified 618 common single nucleotide polymorphisms (SNPs) associated with CRP levels from the NHGRI-EBI GWAS Catalog. Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between SNPs and CRC-specific mortality adjusting for age, sex, genotyping platform/study and principal components. We investigated their interactions with sex and lifestyle factors using likelihood ratio tests. Of 5472 (33.9%) deaths accrued over up to 10 years of follow-up, 3547 (64.8%) were due to CRC. No variants were associated with CRC-specific mortality after multiple comparison correction. We observed strong evidence of interaction between variant rs1933736 at FRK gene and sex in relation to CRC-specific mortality (corrected Pinteraction  = .0004); women had higher CRC-specific mortality associated with the minor allele (HR = 1.11, 95% CI = 1.04-1.19) whereas an inverse association was observed for men (HR = 0.88, 95% CI = 0.82-0.94). There was no evidence of interactions between CRP-associated SNPs and alcohol, obesity or smoking. Our study observed a significant interaction between sex and a CRP-associated variant in relation to CRC-specific mortality. Future replication of this association and functional annotation of the variant are needed.

Genetically Predicted Circulating C-Reactive Protein Concentration and Colorectal Cancer Survival: A Mendelian Randomization Consortium Study

BACKGROUND

A positive association between circulating C-reactive protein (CRP) and colorectal cancer survival was reported in observational studies, which are susceptible to unmeasured confounding and reverse causality. We used a Mendelian randomization approach to evaluate the association between genetically predicted CRP concentrations and colorectal cancer-specific survival.

METHODS

We used individual-level data for 16,918 eligible colorectal cancer cases of European ancestry from 15 studies within the International Survival Analysis of Colorectal Cancer Consortium. We calculated a genetic-risk score based on 52 CRP-associated genetic variants identified from genome-wide association studies. Because of the non-collapsibility of hazard ratios from Cox proportional hazards models, we used the additive hazards model to calculate hazard differences (HD) and 95% confidence intervals (CI) for the association between genetically predicted CRP concentrations and colorectal cancer-specific survival, overall and by stage at diagnosis and tumor location. Analyses were adjusted for age at diagnosis, sex, body mass index, genotyping platform, study, and principal components.

RESULTS

Of the 5,395 (32%) deaths accrued over up to 10 years of follow-up, 3,808 (23%) were due to colorectal cancer. Genetically predicted CRP concentration was not associated with colorectal cancer-specific survival (HD, -1.15; 95% CI, -2.76 to 0.47 per 100,000 person-years; P = 0.16). Similarly, no associations were observed in subgroup analyses by stage at diagnosis or tumor location.

CONCLUSIONS

Despite adequate power to detect moderate associations, our results did not support a causal effect of circulating CRP concentrations on colorectal cancer-specific survival.

IMPACT

Future research evaluating genetically determined levels of other circulating inflammatory biomarkers (i.e., IL6) with colorectal cancer survival outcomes is needed.

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.

Studies in lung cancer cytokine proteomics: a review

INTRODUCTION

Proteins are molecules that have role in the progression of the diseases. Proteomics is a tool that can play an effective role in identifying diagnostic and therapeutic biomarkers for lung cancer. Cytokines are proteins that play a decisive role in activating body's immune system in lung cancer. They can increase the growth of the tumor (oncogenic cytokines) or limit tumor growth (anti-tumor cytokines) by regulating related signaling pathways such as proliferation, growth, metastasis, and apoptosis.

AREAS COVERED

In the present study, a total of 223 papers including 196 research papers and 27 review papers, extracted from PubMed and Scopus and published from 1997 to present, are reviewed. The most important involved-cytokines in lung cancer including TNF-α, IFN- γ, TGF-β, VEGF and interleukins such as IL-6, IL-17, IL-8, IL-10, IL-22, IL-1β and IL-18 are introduced. Also, the pathological and biological role of such cytokines in cancer signaling pathways is explained.

EXPERT OPINION

In lung cancer, the cytokine expression changes under the physiological conditions of the immune system, and inflammatory cytokines are associated with the progression of lung cancer. Therefore, the cytokine expression profile can be used in the diagnosis, prognosis, prediction of therapeutic responses, and survival of patients with lung cancer.

Unactivated leukocyte expression of C-reactive protein is minimal and not dependent on rs1205 genotype

C-reactive protein (CRP), a prominent component of the innate immune system, is implicated in the pathophysiology of many conditions. CRP production primarily occurs in the liver; but contributions from other tissues is unclear. The Genotype-Tissue Expression Portal shows essentially no expression in whole blood and reports in the literature are conflicting. Multiple genomic variants influence serum levels of CRP. We measured CRP mRNA expression in leukocytes and sought to determine if rs1205 genotype influences leukocyte expression. Leukocytes were obtained from 20 women differing by genotype. Quantitative, real-time PCR (RT-qPCR) detected CRP and reference gene (GAPDH) mRNA. Leukocyte expression was calculated by the 2^ΔCT method, and against a standard curve. Digital drop PCR was also used to calculate expression ratios. Student's t test and linear regression methods examined possible differences between genotypes. During 32 runs (10 replicates each), the RT-qPCR mean (SD) CRP/GAPDH ratio was 3.39 × 10^–4 (SD 1.73 × 10^–4) and 3.15 × 10^–4 (SD 1.64 × 10^–4) for TT and CC genotypes respectively, p = 0.76; and digital drop PCR results were similar. Serum CRP was not significantly different between genotypes, nor correlated with leukocyte expression. CRP is minimally expressed in unactivated leukocytes and this expression is not likely influenced by rs1205 genotype.

A Functional Genetic Variant at the C-Reactive Protein Promoter (rs3091244) Is Not Associated With Cancer Risk in a Chinese Population

Background: The association of genetically elevated levels of circulating C-reactive protein (CRP) with cancer risk has been extensively investigated in European populations; however, there are conflicting conclusions. The tri-allelic rs3091244 is a functionally validated genetic variant, and its allelic frequencies differ significantly between European and Asian populations. Here, we examined the association of rs3091244 with cancer risk in a Chinese population. Methods: rs3091244 was genotyped by Sanger sequencing in 4,971 cancer cases and 2,485 controls. The rs1205 and rs2794521 gene variants were also genotyped using TaqMan assays in subgroups. Results: No association was detected between the genotyped CRP variants and cancer risk, with or without distinguishing cancer types, suggesting that circulating CRP is not causally involved in tumorigenesis in Chinese populations.

Association of C-reactive protein (CRP) rs1205 and rs2808630 variants and risk of cancer

The correlation between rs1205, rs2808630 variants of C-reactive protein (CRP) gene and susceptibility of cancer has been assessed previously, but with conflicting results. We adopted odds ratios (ORs) with 95% confidence intervals (CIs), in silico tools and enzyme-linked immunosorbent assay (ELISA) analysis to evaluate this association. Totally, 10,614 cancer subjects and 33,294 controls were involved in the pooled analysis. When all the studies were pooled, no significant correlation was indicated between the two variants and cancer risk. However, in stratification analysis by ethnicity, we found that CRP rs1205 C>T polymorphism was associated with an elevated risk of cancer in Asians (T-allele vs. C-allele, OR = 1.20, 95% CI = 1.06-1.36, p_{heterogeneity}  = .226; TT vs. CC, OR = 1.48, 95% CI = 1.14-1.93, p_{heterogeneity}  = .089). Similar findings were observed for rs2808630 variant. In silico tools showed that lung adenocarcinoma participants with high CRP expression may have shorter overall survival time than low expression group. ELISA analysis indicated that CRP expression in prostate adenocarcinoma subjects with TT + TC genotypes was statistically higher than in those with CC genotypes. CRP rs1205 C>T and rs2808630 T>C polymorphism may be associated with cancer risk, especially for Asians.

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.

MicroRNA binding site polymorphism in inflammatory genes associated with colorectal cancer: literature review and bioinformatics analysis

Inflammation, among environmental risk factors, is one of the most important contributors to colorectal cancer (CRC) development. In this way, studies revealed that the incidence of CRC in inflammatory bowel disease patients is up to 60% higher than the general population. MicroRNAs (miRNAs), small noncoding RNA molecules, have attracted excessive attention due to their fundamental role in various aspects of cellular biology, such as inflammation by binding to the 3'-untranslated regions (3'-UTR) of pro and anti-inflammatory genes. Based on multiple previous studies, SNPs at 3'-UTR can affect miRNA recognition elements by changing the thermodynamic features and secondary structure. This effect can be categorized, based on the number of changes, into four groups, including break, decrease, create, and enhance. In this paper, we will focus on functional variants in miRNA binding sites in inflammatory genes, which can modulate the risk of CRC by both investigating previous studies, regarding miRSNPs in inflammatory genes associated with CRC and recruiting in silico prediction algorithms to report putative miRSNPs in 176 inflammatory genes. In our analysis, we achieved 110 miRSNPs in 3'-UTR of 67 genes that seem good targets for future researches.

MicroRNA-binding site polymorphisms and risk of colorectal cancer: A systematic review and meta-analysis

Genetic variations in miRNAs binding site might participate in cancer risk. This study aimed to systematically review the association between miRNA-binding site polymorphisms and colorectal cancer (CRC). Electronic literature search was carried out on PubMed, Web of Science (WOS), Scopus, and Embase. All types of observational studies till 30 November 2018 were included. Overall 85 studies (21 SNPs) from two systematic searches were included analysis. The results showed that in the Middle East population, the minor allele of rs731236 was associated with decreased risk of CRC (heterozygote model: 0.76 [0.61-0.95]). The minor allele of rs3025039 was related to increased risk of CRC in East Asian population (allelic model: 1.25 [1.01-1.54]). Results for rs3212986 were significant in overall and subgroup analysis (P < .05). For rs1801157 in subgroup analysis the association was significant in Asian populations (including allelic model: 2.28 [1.11-4.69]). For rs712, subgroup analysis revealed a significant (allelic model: 1.41 [1.23-1.61]) and borderline (allelic model: 0.92 [0.84-1.00]) association in Chinese and Czech populations, respectively. The minor allele of rs17281995 increased risk of CRC in different genetic models (P < .05). Finally, rs5275, rs4648298, and rs61764370 did not show significant associations. In conclusion, minor allele of rs3025039, rs3212986, and rs712 polymorphisms increases the risk of CRC in the East Asian population, and heterozygote model of rs731236 polymorphism shows protective effect in the Middle East population. In Europeans, the minor allele of rs17281995 may increase the risk of CRC, while rs712 may have a protective effect. Further analysis based on population stratifications should be considered in future studies.

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.

C-reactive protein gene 1846C>T polymorphism is associated with increased risk and clinical features of lung cancer: a case-control study

Chronic inflammation plays an important role in lung carcinogenesis. Recently, several studies investigated the association of C-reactive protein (CRP) gene 1846C>T polymorphism and lung cancer (LC) risk, but with conflicting findings. In the present study, we conducted this case-control study with 408 LC patients and 472 healthy controls in a Chinese Han population. Genotyping was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLR) method. Our data found that CRP gene 1846C>T polymorphism increased the risk of LC. Subgroup analyses obtained significant associations among the groups of males, ≥50 years old, smoking, and non-drinkers. Bioinformatics analysis showed that the expression levels of CRP in LC tissues were significantly increased compared with normal tissues. Additionally, the present study found CRP mRNA high expression was associated with worse survival in LC patients. Furthermore, our data indicated that TT genotype of 1846C>T polymorphism was associated with a larger size of tumor and was related with lymphatic metastasis in LC patients. In conclusion, the present study suggests that CRP gene 1846C>T polymorphism is associated with increased risk of LC. CRP gene 1846C>T polymorphism may be a potential marker for the diagnosis of LC.

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.

Polymorphisms in genes related to inflammation and obesity and colorectal adenoma risk

We previously investigated the association between single nucleotide polymorphisms (SNPs) in genes related to obesity and inflammation and colorectal cancer in the CLUE II cohort. However, the relationships between these SNPs and colorectal adenomas have not been well evaluated. In a nested case-control study of 135 incident adenoma cases and 269 matched controls in the CLUE II cohort (1989-2000), we genotyped 17 candidate SNPs in 12 genes (PPARG, TCF7L2, ADIPOQ, LEP, IL10, CRP, TLR4, IL6, IL1B, IL8, TNF, RNASEL) and 19 tagSNPs in three genes (IL10, CRP, and TLR4). Conditional logistic regression was used to calculate odds ratios (OR) for adenomas (overall and by size, histology, location, number). Polymorphisms in the inflammatory-related genes CRP, ADIPOQ, IL6, and TLR4 were observed to be associated with adenoma risk. At rs1205 in CRP, T (minor allele) carriers had a higher risk (OR 1.67, 95%CI 1.07-2.60; reference: CC) of adenomas overall and adenomas with aggressive characteristics. At rs1201299 in ADIPOQ, the AC genotype had a higher risk (OR 1.58, 95%CI 1.00-2.49) of adenomas, while the minor AA genotype had a borderline inverse association (OR 0.44, 95%CI 0.18-1.08; reference: CC). At rs1800797 in IL6, the AA genotype had a borderline inverse association (OR 0.53, 95%CI 0.27-1.05; reference: GG). Three TLR4 tagSNPs (rs10116253, rs1927911, rs7873784) were associated with adenomas among obese participants. None of these SNPs were associated with colorectal cancer in our prior study in CLUE II, possibly suggesting a different genetic etiology for early colorectal neoplasia.

Serum C-reactive protein is an important and powerful prognostic biomarker in most adult solid tumors

INTRODUCTION

Prognostication in cancer is challenging and inaccurate. C-Reactive Protein (CRP), a cheap and sensitive marker of inflammation may help. This study investigated the relationship between CRP and prognosis in a large cohort of solid tumors with mixed cancer diagnoses and stages.

METHODS

Electronic medical records of 4931 adults with solid tumors who attended the Taussig Cancer Institute from 2006-2012 were reviewed. Demographic and clinical characteristics were recorded. Maximum CRP (mCRP) was identified for each individual. CRP was analysed as a time-dependent, continuous and categorical variable for association with survival.

RESULTS

Two thirds of patients had a high mCRP. This was consistently associated with shorter survival, even after correction for time from diagnosis, and when analysed as a continuous or a categorical variable. When mCRP values above 10 mg/L were subcategorized, a higher mCRP was always worse. Even among those with normal values, statistically and clinically significant shorter survival was noted at mCRP levels >5 mg/L.

CONCLUSIONS

In a large representative cohort of consecutive solid tumor patients the risk of death was clinically and statistically significantly greater with a high mCRP. This was independent of other variables and regardless of statistical method from both dates of diagnosis and test. CRP appeared to be underutilized. Our results support the routine use of CRP as a universal cost-effective independent prognostic indicator in most solid tumors.

Discovery, fine-mapping, and conditional analyses of genetic variants associated with C-reactive protein in multiethnic populations using the Metabochip in the Population Architecture using Genomics and Epidemiology (PAGE) study

C-reactive protein (CRP) is a circulating biomarker indicative of systemic inflammation. We aimed to evaluate genetic associations with CRP levels among non-European-ancestry populations through discovery, fine-mapping and conditional analyses. A total of 30 503 non-European-ancestry participants from 6 studies participating in the Population Architecture using Genomics and Epidemiology study had serum high-sensitivity CRP measurements and ∼200 000 single nucleotide polymorphisms (SNPs) genotyped on the Metabochip. We evaluated the association between each SNP and log-transformed CRP levels using multivariate linear regression, with additive genetic models adjusted for age, sex, the first four principal components of genetic ancestry, and study-specific factors. Differential linkage disequilibrium patterns between race/ethnicity groups were used to fine-map regions associated with CRP levels. Conditional analyses evaluated for multiple independent signals within genetic regions. One hundred and sixty-three unique variants in 12 loci in overall or race/ethnicity-stratified Metabochip-wide scans reached a Bonferroni-corrected P-value <2.5E-7. Three loci have no (HACL1, OLFML2B) or only limited (PLA2G6) previous associations with CRP levels. Six loci had different top hits in race/ethnicity-specific versus overall analyses. Fine-mapping refined the signal in six loci, particularly in HNF1A. Conditional analyses provided evidence for secondary signals in LEPR, IL1RN and HNF1A, and for multiple independent signals in CRP and APOE. We identified novel variants and loci associated with CRP levels, generalized known CRP associations to a multiethnic study population, refined association signals at several loci and found evidence for multiple independent signals at several well-known loci. This study demonstrates the benefit of conducting inclusive genetic association studies in large multiethnic populations.

C-reactive protein gene rs1205 polymorphism is not associated with the risk of colorectal cancer

The relationship between C-reactive protein (CRP) gene rs1205 polymorphism and the risk of colorectal cancer (CRC) has been investigated previously. However, the results were conflicting. In the present study, we assessed whether CRP gene rs1205 polymorphism was associated with the risk of CRC by meta-analysis. We searched in PubMed, Embase, and the CNKI databases. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. Seven original studies involving 4,181 cases and 10,601 controls analyzed the association between CRP gene rs1205 polymorphism and CRC risk. No significant association was found between CRP gene rs1205 polymorphism and CRC risk in this meta-analysis. Sensitivity analysis did not draw different findings. Stratification analyses of ethnicity, type of cancer, and genotype method also did not obtain any association between CRP gene rs1205 polymorphism and CRC risk. In conclusion, this meta-analysis indicates that CRP gene rs1205 polymorphism was not associated with the risk of CRC.

Adolescent body mass index and erythrocyte sedimentation rate in relation to colorectal cancer risk

OBJECTIVE

Adult obesity and inflammation have been associated with risk of colorectal cancer (CRC); however, less is known about how adolescent body mass index (BMI) and inflammation, as measured by erythrocyte sedimentation rate (ESR), relate to CRC risk. We sought to evaluate these associations in a cohort of 239 658 Swedish men who underwent compulsory military enlistment examinations in late adolescence (ages 16-20 years).

DESIGN

At the time of the conscription assessment (1969-1976), height and weight were measured and ESR was assayed. By linkage to the national cancer registry, these conscripts were followed for CRC through 1 January 2010. Over an average of 35 years of follow-up, 885 cases of CRC occurred, including 501 colon cancers and 384 rectal cancers. Cox regression was used to estimate adjusted HRs and corresponding 95% CIs.

RESULTS

Compared with normal weight (BMI 18.5 to <25 kg/m(2)) in late adolescence, upper overweight (BMI 27.5 to <30 kg/m(2)) was associated with a 2.08-fold higher risk of CRC (95% CI 1.40 to 3.07) and obesity (BMI 30+ kg/m(2)) was associated with a 2.38-fold higher risk of CRC (95% CI 1.51 to 3.76) (p-trend: <0.001). Male adolescents with ESR (15+ mm/h) had a 63% higher risk of CRC (HR 1.63; 95% CI 1.08 to 2.45) than those with low ESR (<10 mm/h) (p-trend: 0.006). Associations did not significantly differ by anatomic site.

CONCLUSIONS

Late-adolescent BMI and inflammation, as measured by ESR, may be independently associated with future CRC risk. Further research is needed to better understand how early-life exposures relate to CRC.

Review of the Gene-Environment Interaction Literature in Cancer: What Do We Know?

BACKGROUND

Risk of cancer is determined by a complex interplay of genetic and environmental factors. Although the study of gene-environment interactions (G×E) has been an active area of research, little is reported about the known findings in the literature.

METHODS

To examine the state of the science in G×E research in cancer, we performed a systematic review of published literature using gene-environment or pharmacogenomic flags from two curated databases of genetic association studies, the Human Genome Epidemiology (HuGE) literature finder and Cancer Genome-Wide Association and Meta Analyses Database (CancerGAMAdb), from January 1, 2001, to January 31, 2011. A supplemental search using HuGE was conducted for articles published from February 1, 2011, to April 11, 2013. A 25% sample of the supplemental publications was reviewed.

RESULTS

A total of 3,019 articles were identified in the original search. From these articles, 243 articles were determined to be relevant based on inclusion criteria (more than 3,500 interactions). From the supplemental search (1,400 articles identified), 29 additional relevant articles (1,370 interactions) were included. The majority of publications in both searches examined G×E in colon, rectal, or colorectal; breast; or lung cancer. Specific interactions examined most frequently included environmental factors categorized as energy balance (e.g., body mass index, diet), exogenous (e.g., oral contraceptives) and endogenous hormones (e.g., menopausal status), chemical environment (e.g., grilled meats), and lifestyle (e.g., smoking, alcohol intake). In both searches, the majority of interactions examined were using loci from candidate genes studies and none of the studies were genome-wide interaction studies (GEWIS). The most commonly reported measure was the interaction P-value, of which a sizable number of P-values were considered statistically significant (i.e., <0.05). In addition, the magnitude of interactions reported was modest.

CONCLUSION

Observations of published literature suggest that opportunity exists for increased sample size in G×E research, including GWAS-identified loci in G×E studies, exploring more GWAS approaches in G×E such as GEWIS, and improving the reporting of G×E findings.

Genetic polymorphisms in C-reactive protein increase cancer susceptibility

Elevated levels of C-reactive protein (CRP) partially induced by polymorphisms in the CRP gene have been associated with human cancer. The purpose of this study was to test the hypothesis that CRP gene polymorphisms (+942G>C, 1846C>T) modify inherited susceptibility to cancer. We systematically identified the publications addressing the association of CRP gene polymorphisms with cancer susceptibility. Studies that fulfilled all inclusion criteria were considered eligible in this meta-analysis. We analyzed a total of 8 case-control studies. Individuals with the CC genotype were found to have an almost 4 fold higher risk of cancer than those with the GG or GC and GG genotypes. A significant association was also indicated in subgroup of colorectal cancer. Meta-analysis of 1846C>T polymorphism showed increased cancer risk in relation to the 1846 TT genotype (TT vs. CC: OR = 1.15, 95% CI = 1.01–1.31; TT vs. CT + CC; OR = 1.17, 95% CI = 1.03–1.32). Similar results were suggested in Caucasian populations and colorectal cancer. These data suggest that both +942G>C and 1846C>T polymorphisms in the CRP gene may influence cancer susceptibility.

C-Reactive Protein Is an Important Biomarker for Prognosis Tumor Recurrence and Treatment Response in Adult Solid Tumors: A Systematic Review

PURPOSE

A systematic literature review was done to determine the relationship between elevated CRP and prognosis in people with solid tumors. C-reactive protein (CRP) is a serum acute phase reactant and a well-established inflammatory marker. We also examined the role of CRP to predict treatment response and tumor recurrence.

METHODS

MeSH (Medical Subject Heading) terms were used to search multiple electronic databases (PubMed, EMBASE, Web of Science, SCOPUS, EBM-Cochrane). Two independent reviewers selected research papers. We also included a quality Assessment (QA) score. Reports with QA scores <50% were excluded. PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) methodology was utilized for this review (S1 PRISMA Checklist).

RESULTS

271 articles were identified for final review. There were 45% prospective studies and 52% retrospective. 264 had intermediate QA score (≥50% but <80%); Seven were adequate (80% -100%); A high CRP was predictive of prognosis in 90% (245/271) of studies-80% of the 245 studies by multivariate analysis, 20% by univariate analysis. Many (52%) of the articles were about gastrointestinal malignancies (GI) or kidney malignancies. A high CRP was prognostic in 90% (127 of 141) of the reports in those groups of tumors. CRP was also prognostic in most reports in other solid tumors primary sites.

CONCLUSIONS

A high CRP was associated with higher mortality in 90% of reports in people with solid tumors primary sites. This was particularly notable in GI malignancies and kidney malignancies. In other solid tumors (lung, pancreas, hepatocellular cancer, and bladder) an elevated CRP also predicted prognosis. In addition there is also evidence to support the use of CRP to help decide treatment response and identify tumor recurrence. Better designed large scale studies should be conducted to examine these issues more comprehensively.

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.

Association of CRP genetic variants with blood concentrations of C-reactive protein and colorectal cancer risk

High blood concentrations of C-reactive protein (CRP) have been associated with elevated risk of colorectal cancer in several prospective studies including the European Prospective Investigation into Cancer and Nutrition (EPIC), but it is unknown whether these observations reflect a causal relationship. We aimed to investigate whether CRP genetic variants associated with lifelong higher CRP concentrations translate into higher colorectal cancer risk. We conducted a prospective nested case-control study within EPIC including 727 cases diagnosed between 1992 and 2003 and 727 matched controls selected according to an incidence-density sampling protocol. Baseline CRP concentrations were measured in plasma samples by a high sensitivity assay. Tagging single nucleotide polymorphisms (SNPs) in the CRP gene (rs1205, rs1800947, rs1130864, rs2808630, rs3093077) were identified via HapMap. The causal effect of CRP on colorectal cancer risk was examined in a Mendelian Randomization approach utilizing multiple CRP genetic variants as instrumental variables. The SNPs rs1205, rs1800947, rs1130864 and rs3093077 were significantly associated with CRP concentrations and were incorporated in a CRP allele score which was associated with 13% higher CRP concentrations per allele count (95% confidence interval 8-19%). Using the CRP-score as instrumental variable, genetically twofold higher CRP concentrations were associated with higher risk of colorectal cancer (odds ratio 1.74, 95% confidence interval 1.06-2.85). Similar observations were made using alternative definitions of instrumental variables. Our findings give support to the hypothesis that elevated circulating CRP may play a direct role in the etiology of colorectal cancer.

Quantitative analysis of the association between CRP rs2808630 and rs1417938 polymorphisms and cancer risk

Accumulating evidence indicates that polymorphisms in the CRP gene are important in the development of cancer. The current meta-analysis was performed to investigate the association between CRP polymorphisms 3407 A>G (rs2808630) and 29 A>T (rs1417938), and the risk of developing cancer. A search of the relevant literature was conducted using the PubMed database to identify eligible studies published up until March 25, 2014. Five case-control studies involving 888 cases and 3,167 controls for the 3407 A>G polymorphism, and six case-control studies involving 3,110 cases and 5,951 controls for the 29 A>T polymorphism were included in the current meta-analysis. The pooled odds ratios with 95% confidence intervals were calculated using the fixed- or random-effects model. Meta-analysis identified no association between the CRP 3407 A>G and 29 A>T polymorphisms, and overall cancer risk. Additional stratified analysis by cancer type did not reveal any significant associations in the genetic models investigated. The findings of the present study indicated that CRP 3407 A>G and 29 A>T polymorphisms are not associated with cancer risk.

CRP 1059 G/C and 1846G/A polymorphisms and cancer risk: a meta-analysis of 26,634 subjects

BACKGROUND AND OBJECTIVE

Previous studies have shown that C-reactive protein (CRP) 1059G/C and 1846G/A polymorphisms may play a role in cancer risk. However, the results from the published studies are conflicting. To derive a more precise estimation of the relationship between CRP 1059G/C and 1846G/A polymorphisms and cancer risk, we conducted a meta-analysis of 21 studies involving a total of 26,634 subjects.

METHODS

Odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of the association.

RESULTS

No significant association was found between CRP 1846G/A polymorphism and cancer risk. However, a significant association was found between CRP 1059G/C polymorphism and cancer risk (CC vs CG+GG: OR=3.60, 95% CI=1.63-7.92, PH=0.67; CC vs GG: OR=3.53, 95% CI=1.60-7.77, PH=0.69). In the subgroup analysis by ethnicity, a significant association was found for the CRP 1846G/A polymorphism among mixed population. Interestingly, when stratifying by cancer type, marginally increased risks were observed for CRP 1846G/A polymorphism in colorectal cancer (AA vs AG+GG: OR=1.17, 95% CI=1.00-1.36, PH=0.27) and significantly decreased risks were found for CRP 1846G/A polymorphism in breast cancer (AA vs GG: OR=0.73, 95% CI=0.56-0.95, PH=0.93; A vs G: OR=0.88, 95% CI=0.79-0.99, PH=0.54). For 1059G/C polymorphism, a significant association was found in colorectal cancer.

CONCLUSION

This meta-analysis showed the evidence that CRP 1059G/C and 1846G/A polymorphisms were risk factors for the development of colorectal cancer, and CRP 1846G/A polymorphism is also a protective factor for decreasing breast cancer.

C-reactive protein and risk of colorectal adenomas or serrated polyps: a prospective study

Serum C-reactive protein (CRP) is a sensitive marker of systemic inflammation. Because there is a well-recognized relationship between local inflammation and colorectal cancer, we aimed to evaluate whether serum CRP levels were associated with the occurrence of colorectal adenomas and serrated polyps using data from a large adenoma prevention trial. A total of 930 participants with a history of colorectal adenomas were enrolled in a randomized trial of calcium supplementation (1,200 mg/day) for the prevention of colorectal adenomas. Outcomes in this analysis are metachronous adenomas (and advanced neoplasms specifically), and serrated polyps at follow-up colonoscopy. High-sensitivity CRP levels were measured 1 year following baseline colonoscopy. Multivariate analysis was performed to estimate risk ratios (RR) using Poisson regression, controlling for potential confounders. We measured serum CRP levels in 689 participants (mean CRP, 3.62 ± 5.72 mg/L). There was no difference in CRP levels with respect to calcium versus placebo treatment assignment (P = 0.99). After adjustment for potential confounders, we found no association between CRP level and risk of recurrent adenoma or advanced lesion [quartile 4 vs. quartile 1: RR, 95% confidence interval (CI) = 0.99 (0.73-1.34) and 0.92 (0.49-1.75), respectively]. Similarly, no association was seen between CRP levels and risk of serrated polyps or proximal serrated polyps [quartile 4 vs. quartile 1: RR (95% CI) = 1.32 (0.85-2.03) and 1.19 (0.54-2.58), respectively]. In conclusion, this large prospective colorectal adenoma chemoprevention study found no significant relationship between CRP levels and occurrence of adenomas, advanced neoplasms, or serrated polyps.

Genetic variation across C-reactive protein and risk of prostate cancer

BACKGROUND

Inflammation has been hypothesized to play an important etiological role in the initiation or progression of prostate cancer. Circulating levels of the systemic inflammation marker C-reactive protein (CRP) have been associated with increased risk of prostate cancer. We investigated the role of genetic variation in CRP and prostate cancer, under the hypothesis that variants may alter risk of disease.

METHODS

We undertook a case-control study nested within the prospective Physicians' Health Study among 1,286 men with incident prostate cancer and 1,264 controls. Four single-nucleotide polymorphisms (SNPs) were selected to capture the common genetic variation across CRP (r(2)  > 0.8). We used unconditional logistic regression to assess the association between each SNP and risk of prostate cancer. Linear regression models explored associations between each genotype and plasma CRP levels.

RESULTS

None of the CRP SNPs were associated with prostate cancer overall. Individuals with one copy of the minor allele (C) in rs1800947 had an increased risk of high-grade prostate cancer (OR: 1.7; 95% CI: 1.1-2.8), and significantly lower mean CRP levels (P-value <0.001), however, we found no significant association with lethal disease. Mean CRP levels were significantly elevated in men with one or two copies of the minor allele in rs3093075 and rs1417939, but these were unrelated to prostate cancer risk.

CONCLUSION

Our findings suggest that SNPs in the CRP gene are not associated with risk of overall or lethal prostate cancer. Polymorphisms in CRP rs1800947 may be associated with higher grade disease, but our results require replication in other cohorts.

C-reactive protein and colorectal cancer mortality in U.S. adults

BACKGROUND

Chronic inflammation has been associated with colorectal cancer. Prediagnostic levels of C-reactive protein (CRP), a highly sensitive marker of inflammation, have been weakly associated with increased colorectal cancer incidence, but few data are available examining its relationship with colorectal cancer mortality.

METHODS

In the Third National Health and Nutrition Examination Survey (NHANES III), 65% of the 15,924 adult participants had CRP levels ≤0.21 mg/dL. Using this as the reference group, we calculated hazard ratios (HR) for higher CRP categories and colorectal cancer mortality, and compared them with HRs for other mortality causes.

RESULTS

Over a median follow-up period of 14.2 years, there were 92 deaths from colorectal cancer. Compared with the reference group, multivariable adjusted HRs for colorectal cancer mortality were 2.66 [95% confidence interval (CI), 1.36-5.20] for CRP levels 0.22-0.50 mg/dL; 3.40 (95% CI, 1.48-7.77) for levels 0.51-1.00 mg/dL; and 3.96 (95% CI, 1.64-9.52) for levels >1.00 mg/dL. Estimates for colorectal cancer mortality did not change appreciably after excluding deaths within the first 3 years or by limiting follow-up to 5 or 10 years.

CONCLUSIONS

In a large representative study of U.S. adults, we observed strong dose-response associations between CRP levels and colorectal cancer mortality.

IMPACT

Further evaluation of CRP may help identify high-risk groups for colorectal cancer screening and those who might benefit most from prophylactic anti-inflammatory therapy.

Multiancestral analysis of inflammation-related genetic variants and C-reactive protein in the population architecture using genomics and epidemiology study

BACKGROUND

C-reactive protein (CRP) is a biomarker of inflammation. Genome-wide association studies (GWAS) have identified single-nucleotide polymorphisms (SNPs) associated with CRP concentrations and inflammation-related traits such as cardiovascular disease, type 2 diabetes mellitus, and obesity. We aimed to replicate previous CRP-SNP associations, assess whether these associations generalize to additional race/ethnicity groups, and evaluate inflammation-related SNPs for a potentially pleiotropic association with CRP.

METHODS AND RESULTS

We selected and analyzed 16 CRP-associated and 250 inflammation-related GWAS SNPs among 40 473 African American, American Indian, Asian/Pacific Islander, European American, and Hispanic participants from 7 studies collaborating in the Population Architecture using Genomics and Epidemiology (PAGE) study. Fixed-effect meta-analyses combined study-specific race/ethnicity-stratified linear regression estimates to evaluate the association between each SNP and high-sensitivity CRP. Overall, 18 SNPs in 8 loci were significantly associated with CRP (Bonferroni-corrected P<3.1×10(-3) for replication, P<2.0×10(-4) for pleiotropy): Seven of these were specific to European Americans, while 9 additionally generalized to African Americans (1), Hispanics (5), or both (3); 1 SNP was seen only in African Americans and Hispanics. Two SNPs in the CELSR2/PSRC1/SORT1 locus showed a potentially novel association with CRP: rs599839 (P=2.0×10(-6)) and rs646776 (P=3.1×10(-5)).

CONCLUSIONS

We replicated 16 SNP-CRP associations, 10 of which generalized to African Americans and/or Hispanics. We also identified potentially novel pleiotropic associations with CRP for two SNPs previously associated with coronary artery disease and/or low-density lipoprotein-cholesterol. These findings demonstrate the benefit of evaluating genotype-phenotype associations in multiple race/ethnicity groups and looking for pleiotropic relationships among SNPs previously associated with related phenotypes.

Recent advances in personalized colorectal cancer research

Colorectal cancer is one of the most prevalent cancers and a leading cause ofcancer-related death. It is also curable if detected early. The prognosis for metastatic colorectal cancer remains poor and resistance to chemotherapy is still a major obstacle in effective treatment. While many patients do not clinically benefit from chemotherapy, others experience adverse reactions resulting in dose modifications or treatment withdrawal, thereby reducing treatment efficacy. Researchefforts attempt to identify reliable biomarkers which will guide clinicians in decision making, while matching suitable therapeutic regimens. We here review currently known molecular biomarkers used for the personalized treatment of colorectal cancer.

Impact of genetic polymorphisms on adenoma recurrence and toxicity in a COX2 inhibitor (celecoxib) trial: results from a pilot study

OBJECTIVE

Chemoprevention trials have shown that celecoxib reduces adenoma recurrence but can cause cardiovascular toxicity. In this pilot study, we evaluated associations between genetic variation in several candidate pathways (e.g. prostaglandin synthesis) and adenoma recurrence and cardiovascular and gastrointestinal toxicities.

METHODS

Genotyping analysis was carried out on 117 Israeli colorectal adenoma patients who participated in the Prevention of Colorectal Sporadic Adenomatous Polyps trial. Reassessment followed after 3 years on celecoxib and after 2 years from termination of treatment with celecoxib. Efficacy (absence of colorectal adenomas) was measured by colonoscopy at years 1, 3, and 5. Toxicities were assessed by investigators during celecoxib treatment and by self-report post-treatment. A linkage disequilibrium-based selection algorithm (r2≥0.90, MAF≥4%) identified 255 tagSNPs in 25 analyzed candidate genes. Genotyping was performed by using Illumina GoldenGate technology.

RESULTS

Multiple genetic variants were associated with adenoma recurrence and toxicity. Genetic variability in COX1, COX2, and ALOX12/15 genes played a role in adenoma recurrence, particularly among patients on placebo. More gene variants (especially variants in PGES, CRP, SRC, and GPX3) were associated with increased risk for cardiovascular toxicity and symptoms, compared with gastrointestinal toxicity and symptoms. The increased risk for cardiovascular toxicity/symptoms associated with the SRC gene variants (rs6017996, rs6018256, rs6018257) ranged from 6.61 (95% confidence interval 1.66-26.36, P<0.01) to 10.71 (95% confidence interval 1.96-58.60, P<0.01).

CONCLUSION

Genetic polymorphisms in multiple inflammation-related genes appear to interact with celecoxib on adenoma recurrence and its attendant toxicity, particularly cardiovascular toxicity/symptoms. Larger studies validating these pharmacogenetic relationships are needed.

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

PURPOSE

Many studies, including the Atherosclerosis Risk in Communities (ARIC) cohort, reported a positive association between plasma C-reactive protein (CRP)-a biomarker of low-grade chronic inflammation-and colorectal cancer risk, although it is unclear whether the association is causal. Our aims were to assess the associations of a CRP genetic risk score (CRP-GRS) created from single-nucleotide polymorphisms (SNPs) with colorectal cancer risk, as well as examine plasma CRP and CRP-GRS in relation to common cancers in the ARIC cohort.

METHODS

Cox proportional hazards models were used to prospectively estimate hazard ratios (HRs) and 95 % confidence interval (95 % CI) of total, colorectal, lung, prostate, and breast cancers in relation to: (1) CRP-GRS among 8,657 Whites followed in 1987-2006 and (2) log-transformed plasma CRP among 7,603 Whites followed in 1996-2006. A weighted CRP-GRS was comprised of 20 CRP-related SNPs located in/near CRP, APOC1, HNF1A, LEPR, and 16 other genes that were identified in genome-wide association studies.

RESULTS

After multivariable adjustment, one standard deviation increment of the CRP-GRS was associated with colorectal cancer risk (HR 1.19; 95 % CI 1.03-1.37), but not with any other cancer. One unit of log-transformed plasma CRP was associated with the risk of total, colorectal, lung, and breast cancers: HRs (95 % CIs) were 1.08 (1.01-1.15), 1.24 (1.01-1.51), 1.29 (1.08-1.54), and 1.27 (1.07-1.51), respectively. HRs remained elevated, although lost statistical significance for all but breast cancer, after excluding subjects with <2 years of follow-up.

CONCLUSIONS

The study corroborates a causative role of chronic low-grade inflammation in colorectal carcinogenesis.

High-sensitivity CRP in opiate addiction: relative and age-dependent elevations

High-sensitivity C-reactive protein (hs-CRP) has been shown to be linked with immune stimulation, but is not well studied over the lifetime in opiate addiction. hs-CRP was measured by standard laboratory methods in substance use disorder (SUD) patients and non-SUD (NSUD) aged 18-48 years. Data were log transformed to improve normality. 1231 SUD were compared with 326 NSUD patients of comparable ages. hs-CRP was 7.46 ± 14.24 versus 4.75 ± 13.40 mg/l (mean ± SD) significantly higher in the SUD group (P < 0.0001), a difference which persisted after exclusion of acutely elevated hs-CRP values (P < 0.0001). In multiple regression with age, addictive status was significant both by itself (P < 0.0001) and in interaction with age (P < 0.0001). At age 40 years, the SUD group had a mean hs-CRP of 3.68 which the NSUD group did not achieve till a modelled age of 157.09 years. In an interactive multivariate regression, interactions between age, addictive status, ALT and AST were significant. These data show that hs-CRP is elevated in opiate dependence both per se, and when controlled for age. Furthermore, they suggest that hs-CRP and immune stimulation seen in opiate addiction may underlie the acceleration of age-related multi-system chronic and coronary atherosclerotic disease well described in opiate dependence.

Obesity as a major risk factor for cancer

The number of cancer cases caused by being obese is estimated to be 20% with the increased risk of malignancies being influenced by diet, weight change, and body fat distribution together with physical activity. Reports from the International Agency for Research into Cancer and the World Cancer Research Fund (WCRF) have shown that the strongest evidence exists for an association of obesity with the following cancer types: endometrial, esophageal adenocarcinoma, colorectal, postmenopausal breast, prostate, and renal, whereas the less common malignancies are leukemia, non-Hodgkin's lymphoma, multiple myeloma, malignant melanoma, and thyroid tumours. To be able to develop novel methods in prevention and treatment, we first must understand the underlying processes which link cancer to obesity. Four main systems have been identified as potential producers of cancer in obesity: insulin, insulin-like growth factor-I, sex steroids, and adipokines. Various novel candidate mechanisms have been proposed: chronic inflammation, oxidative stress, crosstalk between tumour cells and surrounding adipocytes, migrating adipose stromal cells, obesity-induced hypoxia, shared genetic susceptibility, and the functional defeat of immune function. Herein, we review the major pathogenic links between obesity and susceptibility to cancer.

Influence of Obesity and Related Metabolic Alterations on Colorectal Cancer Risk

Obesity and related metabolic alterations have been implicated to play a role in colorectal cancer risk. The metabolic syndrome, as assessed according to current international definitions by the key components, abdominal obesity, dyslipidemia, elevated blood pressure, and abnormal glucose metabolism, is associated with colorectal cancer. Recent studies suggest that abdominal obesity and abnormal glucose metabolism may primarily account for this association. Visceral adipose tissue is physiologically more active than subcutaneous adipose tissue and generates hormones and cytokines with inflammatory, metabolic, and direct carcinogenic potential, which may directly or indirectly increase colorectal cancer risk. Current evidence suggests that obesity acts as a risk factor for colorectal cancer by several mechanisms, including chronic low-grade inflammation, hyperinsulinemia, as well as alterations in insulin-like growth factor and adipokine concentrations. Metabolic biomarkers reflecting these processes may not only provide clues for etiological understanding of colorectal carcinogenesis but also might be an alternative way to define an "obesity phenotype" that is relevant for colorectal cancer development.

CpG island methylation in colorectal cancer: past, present and future

The concept of a CpG island methylator phenotype, or CIMP, quickly became the focus of several colorectal cancer studies describing its clinical and pathological features after its introduction in 1999 by Toyota and colleagues. Further characterization of CIMP in tumors lead to widespread acceptance of the concept, as expressed by Shen and Issa in their 2005 editorial, "CIMP, at last." Since that time, extensive research efforts have brought great insights into the epidemiology and prognosis of CIMP+ tumors and other epigenetic mechanisms underlying tumorigenesis. With the advances in technology and subsequent cataloging of the human methylome in cancer and normal tissue, new directions in research to understand CIMP and its role in complex biological systems yield hope for future epigenetically based diagnostics and treatments.