The Performance of Three-Sample Qualitative Immunochemical Fecal Test to Detect Colorectal Adenoma and Cancer in Gastrointestinal Outpatients: An Observational Study

Background

Repeated qualitative fecal immunochemical test (qlFIT) is a clinical strategy widely used to detect lower gastrointestinal lesions, but its diagnostic power has not been assessed in opportunistic screening for colorectal neoplasia.

Objective

This study aimed to determine the performance of three-sample qlFIT in screening for colorectal cancer and its precursors in high-risk participants.

Methods

513 gastrointestinal outpatients yielded three qlFITs before a standard colonoscopy. We evaluated the diagnostic value of one, two, and three positive qlFITs serving as the positivity threshold. The risk factors of colorectal neoplasia to yield positive qlFITs were also determined.

Results

52 patients were diagnosed with colorectal cancer and 70 with advanced adenomatous polyp. For colorectal cancer, the sensitivity and specificity of one positive qlFIT were 90.4% and 53.8%, of two were 80.8% and 75.1%, and of three were 53.9% and 88.5%, respectively. For advanced adenomatous polyp, the sensitivity and specificity of one positive qlFIT were 81.4% and 54.2%, of two were 50.0% and 72.5%, and of three were 28.6% and 86.2%. Left-sided location (OR 2.50, 95%CI 1.26–4.95) and advanced histology of tumors (OR 3.08, 95%CI 1.58–6.01) were independently associated with positive qlFITs.

Conclusions

Three-sample qlFIT is a reasonably good method to detect colorectal neoplasia in high-risk population. Tumors in the left side or with advanced pathological features are more likely to produce positive qlFITs.     

Colonoscopic surveillance of first-degree relatives of colorectal cancer patients in a faecal occult blood screening programme

Background: In some Italian areas, colonoscopic surveillance of first-degree relatives (FDRs) of colorectal cancer (CRC) patients is provided as a part of local population-based faecal occult blood test (FOBT) screening programmes. The objective of the present study was to assess the feasibility and early results of this surveillance model. Methods: Data from district screening centres were used to evaluate the process of identification and selection of eligible FDRs (residence in the Emilia-Romagna Region, age 40–75 years, no recent colonoscopy) of screen-detected CRC patients and the detected prevalence of disease. The probability for an FDR to undergo colonoscopy and to be diagnosed with CRC and advanced adenoma was estimated using the Kaplan–Meier method. The sex- and age-standardised ratio of detected prevalence to that expected based on results from a colonoscopy screening study of the Italian general population was estimated. Results: Between 2005 and 2011, 9319 FDRs of 2437 screen-detected CRC patients (3.8 per patient) were identified and contacted. Their likelihood of being eligible for, and accepting, colonoscopy was 0.11 (95% confidence interval: 0.11–0.12). Among the 926 subjects undergoing colonoscopy, the prevalence of previous negative screening FOBT was 63%. Eleven CRCs (1.2%) and 100 advanced adenomas (10.8%) were detected. The standardised ratio of detected prevalence to that expected was 0.91 (95% confidence interval: 0.19–2.66) for CRC and 1.48 (1.04–2.05) for advanced adenoma. Conclusions: The procedure of selection of FDRs was extremely ineffective. Due to previous negative screening tests, the prevalence of disease was less than expected. A population-based FOBT screening programme is a highly unsuitable setting for the provision of surveillance to FDRs of CRC patients.     

Association between family history of malignant neoplasm with colorectal adenomatous polyp in 40s aged relative person

PurposeWe assessed the association between a family history of malignancy and risk of colorectal adenoma among individuals aged 40–49 years.MethodsThe study population consisted of subjects, aged in their 40s, who underwent colonoscopy. Their family histories of cancer were collected with a self-administered questionnaire. A logistic regression model was used to assess the association between a family history of cancer and the risk of colorectal polyp.ResultsIn total, 2275 participants were included in the study. Univariate analysis showed that old age, male sex, current cigarette smoking, BMI > 25 kg/m², and a family history of colorectal cancer (CRC) were risk factors for the development of sporadic colorectal adenomatous polyps in these patients. A multivariate analysis showed that a family history of CRC or kidney cancer was associated with adenoma development. A family history of CRC was also a risk factor for advanced and multiple adenoma.ConclusionsThis study shows that a family history of CRC is a risk factor for advanced and multiple colorectal adenoma in people in their 40s. These results support earlier screening for colorectal neoplasms in individuals with a family history of CRC.     

Risk of Advanced Neoplasia in First-Degree Relatives with Colorectal Cancer: A Large Multicenter Cross-Sectional Study

BackgroundFirst-degree relatives (FDR) of patients with colorectal cancer have a higher risk of developing colorectal cancer than the general population. For this reason, screening guidelines recommend colonoscopy every 5 or 10 y, starting at the age of 40, depending on whether colorectal cancer in the index-case is diagnosed at <60 or ≥60 y, respectively. However, studies on the risk of neoplastic lesions are inconclusive. The aim of this study was to determine the risk of advanced neoplasia (three or more non-advanced adenomas, advanced adenoma, or invasive cancer) in FDR of patients with colorectal cancer compared to average-risk individuals (i.e., asymptomatic adults 50 to 69 y of age with no family history of colorectal cancer).ConclusionsIndividuals having two FDR with colorectal cancer showed an increased risk of advanced neoplasia compared to those with average-risk for colorectal cancer. Men had over 2-fold higher risk of advanced neoplasia than women, independent of family history. These data suggest that screening colonoscopy guidelines should be revised in the familial-risk population.     

Colorectal cancer incidence in Germany: Stage-shift 6 years after implementation of a colonoscopy screening program

Background: In 2002, colonoscopy was introduced as a tool for colorectal cancer screening in Germany. The long-term objective was to reduce the incidence in colorectal cancer (CRC) by detection and removal of advanced adenomas. Currently, the effect of colonoscopy screening on the population-based incidence of CRC in Germany is unknown. Methods: We provide data on stage-specific (age-standardized) incidence rates in three federal states in Germany, 6 years after the implementation of colonoscopy. Results: Between 2002 and 2008 a statistically significant decrease in CRC incidence could be observed (annually 3.0%, 95% confidence interval [CI]: -3.8; -2.2). The decline could be observed in all advanced tumor categories (T2, T3, and T4), whereas the incidence of in situ carcinomas (Tis) increased annually by 51.6% (95% CI: 28.0; 79.4) until 2004, and remained stable until 2008. Conclusion: The observed changes cannot be attributed definitively to the screening activities, but the presented data support a possible causal association.     

Effectiveness of population-based colorectal cancer screening programme in down-staging

BackgroundThis is the first evaluation study to assess the demographic characteristics of the colorectal cancer (CRC) cases detected in the prevalent round of the population-based Colorectal Cancer Screening Programme (CRCSP) in Hong Kong and to explore the effectiveness of the programme on the stage distribution of CRC.MethodsThis study covered the period between 28 September 2016 and 31 December 2018. Information on CRC diagnosis, age and stage at diagnosis were retrieved and reviewed by the Hong Kong Cancer Registry (HKCaR). The CRC detection rate among CRCSP-screened participants and incidence rate among the Hong Kong general population were calculated respectively. The odds ratio (OR) was calculated to measure the strength of association and quantify the effect of CRCSP on stage shift between CRCSP-detected CRC cases and an age-matched cohort of CRC cases diagnosed outside the programme.ResultsThe CRC detection rate among participants of the CRCSP during the study period was 736.0/100,000, whereas the overall CRC incidence rate among general population of similar age groups was 393.7/100,000. For all ages and both sexes, the OR of stage I CRCSP-detected CRC compared to the CRC from the age-matched cohort was 3.91 (95%CI=3.41–4.48) and the OR dropped to 0.54 (95%CI=0.41–0.70) at stage IV. Meanwhile, the overall OR of CRCSP-detected CRC compared to CRC from the age-matched cohort dropped from 2.24 (95%CI=1.97–2.56) to 1.62 (95%CI=1.40–1.87) with increasing age.ConclusionThe present study has demonstrated the initial impact of the CRCSP on shifting the stage at diagnosis towards earlier stage. The benefit of stage-shift was similar for all ages from 60 to 77 in both sexes and seems to increase with younger age. Given the stage-dependent survival outcomes, this stage-shift could lead to a reduction in CRC-associated mortality in Hong Kong in future.     

No association of XRCC1 polymorphisms Arg194Trp and Arg399Gln with colorectal cancer risk

Background: X-ray repair cross complementation group 1 (XRCC1) plays a key role in base excision repair. The purpose of this study was to examine the association of two genetic polymorphisms in XRCC1 (rs1799782 and rs25487) with risk of colorectal polyps and colorectal cancer (CRC). Methods: In the ongoing colorectal cancer study of Austria (CORSA), a total of 3091 Caucasian participants was genotyped using 5′-nuclease TaqMan assays. Multiple logistic regression was applied to compare individuals of the control group against three different case groups namely CRC cases, high-risk and low-risk polyps. Results: The two investigated SNPs in XRCC1 were not found to be associated with neither CRC risk nor polyp risk. Comparing the CRC cases versus the controls the OR was 0.60 (95%CI 0.27–1.31) for the heterozygous polymorphic genotype of SNP rs1799782 and 1.47 (95%CI 0.81–2.65) for the homozygous polymorphic genotype of SNP rs25487. Comparing the high-risk polyp group versus the controls the OR was 2.64 (95%CI 0.61–11.42) for the homozygous polymorphic genotype of SNP rs1799782 and 0.89 (95%CI 0.60–1.33) for SNP rs25487, respectively. In an haplotype analysis also no statistically significant association was found. Conclusion: Our finding that none of the two investigated SNPs of XRCC1 were significantly associated with risk of CRC or polyps is consistent with the results of a recently published meta-analysis.     

Baseline alcohol consumption,type of alcoholic beverage and risk of colorectal cancer in the European Prospective Investigation into Cancer and Nutrition-Norfolk study

Excessive alcohol consumption has been associated with increased risk of colorectal cancer (CRC). However, the effect of modest alcohol consumption or of particular types of beverages on CRC risk remains unclear. We examined whether consumption of total alcohol or specific types of alcoholic beverages relate to overall or site-specific CRC risk in a prospective population study of 24,244 participants and 407 incident CRC cases after 11 years of follow-up. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models. Consumption of specific alcoholic beverages at baseline was collected using a detailed health and lifestyle questionnaire. Total alcohol consumption was not associated with CRC risk before or after adjustment for age, sex, weight, height, and smoking status (HR: 0.80, 95% CI: 0.51–1.26 for alcohol consumption of ≥21 units/week compared with non-drinkers), and further adjustment for education level, exercise, family history of CRC, and dietary factors did not significantly alter the risk estimates (HR: 0.70, 95% CI: 0.44–1.13). No significant associations were observed between consumption of specific alcoholic beverages (beer, sherry, or spirits) and CRC risk when compared with non-drinkers after adjustment for lifestyle and dietary factors. Daily consumption of ≥1 unit of wine appeared inversely related to CRC risk (HR: 0.61, 95% CI: 0.40–0.94). No evidence was found for sex-specific relationships, and further exclusion of cases incident within 3 years of baseline did not change the associations observed. In this population-based UK cohort, we did not find any significant adverse effect of alcohol over the moderate range of intake on colorectal cancer risk.     

The Joint Effects of Lifestyle Factors and Comorbidities on the Risk of Colorectal Cancer: A Large Chinese Retrospective Case-Control Study

Background

Colorectal cancer (CRC) is a major cause of cancer morbidity and mortality. In previous epidemiologic studies, the respective correlation between lifestyle factors and comorbidity and CRC has been extensively studied. However, little is known about their joint effects on CRC.

Methods

We conducted a retrospective case-control study of 1,144 diagnosed CRC patients and 60,549 community controls. A structured questionnaire was administered to the participants about their socio-demographic factors, anthropometric measures, comorbidity history and lifestyle factors. Logistic regression model was used to calculate the odds ratio (ORs) and 95% confidence intervals (95%CIs) for each factor. According to the results from logistic regression model, we further developed healthy lifestyle index (HLI) and comorbidity history index (CHI) to investigate their independent and joint effects on CRC risk.

Results

Four lifestyle factors (including physical activities, sleep, red meat and vegetable consumption) and four types of comorbidity (including diabetes, hyperlipidemia, history of inflammatory bowel disease and polyps) were found to be independently associated with the risk of CRC in multivariant logistic regression model. Intriguingly, their combined pattern- HLI and CHI demonstrated significant correlation with CRC risk independently (OR_HLI: 3.91, 95%CI: 3.13–4.88; OR_CHI: 2.49, 95%CI: 2.11–2.93) and jointly (OR: 10.33, 95%CI: 6.59–16.18).

Conclusions

There are synergistic effects of lifestyle factors and comorbidity on the risk of colorectal cancer in the Chinese population.     

Predictors of behavioral cancer risk factors and preventive behaviors among Nebraskans

BackgroundThe overall incidence rate of cancer in Nebraska is higher than the national average with cancer being the second leading cause of death in the state. Interventions are required to reduce the cancer burden; however, further research is first needed to identify behavioral cancer risk factors and preventive behaviors among Nebraskans that can be targeted.MethodsA statewide cross-sectional survey of Nebraskans aged 19 and older was conducted in 2019 using an address-based sampling method (n = 1640). Multivariable logistic regression was used to examine factors associated with being up-to-date on cancer screening and with behavioral cancer risk factors and preventive behaviors.Results93.42% of Nebraskans did not meet the daily recommended consumption of fruits and vegetables, and 71.51% did not meet weekly physical activity guidelines. The proportion of adults up to date on cancer screening was 64.57% for breast, 68.83% for cervical, 69.01% for colorectal, and 24.07% for skin cancers. Individuals 65–74 (OR: 3.40, 95% CI: 1.52–7.62) and 75 or older (OR: 3.30, 95% CI: 1.35–8.07) were more likely to be current with their colorectal cancer screening compared to ages 50–64. Hispanics were less likely to be current with mammograms (OR: 0.06, 95% CI: 0.01–0.71) and ever screened for cervical cancer (OR:0.13, 95% CI: 0.02–0.94) compared to Non-Hispanic Whites.ConclusionsDisparities in cancer screening and risk and preventive behaviors exist in Nebraska.ImpactThe study highlights a need for continuing efforts to improve preventive cancer behaviors for the entire population as well as some high-risk populations in Nebraska.     

Risk of advanced colorectal neoplasia according to age and gender

Background

Colorectal cancer (CRC) is one of the leading causes of cancer related morbidity and death. Despite the fact that the mean age at diagnosis of CRC is lower in men, screening by colonoscopy or fecal occult blood test (FOBT) is initiated at same age in both genders. The prevalence of the common CRC precursor lesion, advanced adenoma, is well documented only in the screening population. The purpose of this study was to assess the risk of advanced adenoma at ages below screening age.

Methods and Findings

We analyzed data from a census of 625,918 outpatient colonoscopies performed in adults in Bavaria between 2006 and 2008. A logistic regression model to determine gender- and age-specific risk of advanced neoplasia was developed. Advanced neoplasia was found in 16,740 women (4.6%) and 22,684 men (8.6%). Male sex was associated with an overall increased risk of advanced neoplasia (odds ratio 1.95; 95% confidence interval, CI, 1.91 to 2.00). At any age and in any indication group, more colonoscopies were needed in women than in men to detect advanced adenoma or cancer. At age 75 14.8 (95% CI, 14.4–15.2) screening, 18.2 (95% CI, 17.7–18.7) diagnostic, and 7.9 (95% CI, 7.6–8.2) colonoscopies to follow up on a positive FOBT (FOBT colonoscopies) were needed to find advanced adenoma in women. At age 50 39.0 (95% CI, 38.0–40.0) diagnostic, and 16.3 (95% CI, 15.7–16.9) FOBT colonoscopies were needed. Comparable numbers were reached 20 and 10 years earlier in men than in women, respectively.

Conclusions

At any age and independent of the indication for colonoscopy, men are at higher risk of having advanced neoplasia diagnosed upon colonoscopy than women. This suggests that starting screening earlier in life in men than in women might result in a relevant increase in the detection of asymptomatic preneoplastic and neoplastic colonic lesions.     

Atrial Fibrillation and Colonic Neoplasia in African Americans

Background

Colorectal cancer (CRC) and atrial fibrillation/flutter (AF) share several risk factors including increasing age and obesity. However, the association between CRC and AF has not been thoroughly examined, especially in African Americans. In this study we aimed to assess the prevalence of AF and its risk factors in colorectal neoplasia in an African American.

Methods

We reviewed records of 527 African American patients diagnosed with CRC and 1008 patients diagnosed with benign colonic lesions at Howard University Hospital from January 2000 to December 2012. A control group of 731 hospitalized patients without any cancer or colonic lesion were randomly selected from the same time and age range, excluding patients who had diagnosis of both CRC and/or adenoma. The presence or absence of AF was based upon ICD-9 code documentation. The prevalence of AF in these three groups was compared by multivariate logistic regression.

Results

The prevalence of AF was highest among CRC patients (10%) followed by adenoma patients (7.2%) then the control group (5.4%, P for trend = 0.002). In the three groups of participants, older age (P<0.008) and heart failure (P<0.001) were significantly associated with higher risk of AF. After adjusting for these risk factors, CRC (OR: 1.4(95%CI):0.9–2.2, P = 0.2) and adenoma (OR: 1.1(95%CI):0.7–1.6, P = 0.7) were not significantly associated AF compared to control group.

Conclusions

AF is highly prevalent among CRC patients; 1 in 10 patients had AF in our study. The predictors of AF in CRC was similar to that in adenoma and other patients after adjustment for potential confounders suggesting that the increased AF risk in CRC is explained by higher prevalence of AF risk factors.     

Reproductive factors,obesity and risk of colorectal cancer in a cohort of Asian women

BackgroundThis study evaluated reproductive factors and obesity in relation to colorectal cancer (CRC) in Asian women.MethodsThe study cohort comprised 28191 women who were recruited between 1994 and 1997. During 18 years of prospective follow-up, 404 and 212 women developed colon cancer (CC) and rectal cancer (RC) respectively. Cox proportional hazards regression was used.ResultsMenstrual factors were not related to the risk of CRC, CC and RC. Gravidity and parity were not associated with CRC or RC, but women who were ever pregnant had a HR of 1.87 (95%CI 1.12–3.14) compared to those never pregnant, and parous women had a HR of 1.79 (95% CI 1.10–2.92) compared to nulliparous women for CC. Use of oral contraceptives and hormone replacement therapy were not associated with CRC, CC or RC.Compared to women with normal BMI, women who were obese had HRs of 1.39 (95%CI 1.12–1.74) and 1.64 (95%CI 1.24–2.16) for CRC and CC respectively. No increased risk was seen for RC. Adjusted for BMI, for colonic cancer, women in the highest quartile for Waist Circumference had a HR of 2.14 (95%CI 1.42–3.25) compared to the lowest quartile, for Waist Hip Ratio, a HR of 1.74 (95%CI 1.30–2.34), and for Waist-Height ratio, a HR of 1.80 (1.26–2.57). None of these measures were significantly associated with RC.ConclusionsObesity is positively associated with CC but not RC, and abdominal obesity exerts an independent effect. Reproductive factors had at best a weak effect on CC and RC.     

Prevalence and prognosis of synchronous colorectal cancer: a Dutch population-based study

Background: A noticeable proportion of colorectal cancer (CRC) patients are diagnosed with synchronous CRC. Large population-based studies on the incidence, risk factors and prognosis of synchronous CRC are, however, scarce, and are needed for better determination of risks of synchronous CRC in patients diagnosed with colonic neoplasia. Methods: All newly diagnosed CRC between 1995 and 2006 were obtained from the Rotterdam Cancer Registry in The Netherlands, and studied for synchronous CRC. Results: Of the 13,683 patients diagnosed with CRC, 534 patients (3.9%) were diagnosed with synchronous CRC. The risk of having synchronous CRC was significantly higher in men (OR 1.54, 95% CI 1.29–1.84) and in patients aged >70 years (OR 1.83, 95% CI 1.39–2.40). Synchronous CRC patients had a significantly higher risk of distant metastases (OR 1.69, 95% CI 1.27–2.26). In 34% (184/534) the two tumours were located in different surgical segments. Five-year relative survival of synchronous CRC was similar to patients with solitary CRC after multivariate adjustment for the presence of distant metastases. Conclusion: One out of 25 patients diagnosed with CRC presents with synchronous CRC. In the multivariate analysis, survival of patients with synchronous CRC was similar to patients with solitary CRC, when corrected for the presence of distant metastases at first presentation. One third of the synchronous CRC were located in different surgical segments, which stresses the importance of performing total colon examination preferably prior to surgery.     

Should Prior FIT Results Be Incorporated as an Additional Variable to Estimate Risk of Colorectal Neoplasia? A Prospective Study of 5,813 Screening Colonoscopies

Background

Recent studies showed that previous negative results from faecal immunochemical tests (FITs) for colorectal cancer (CRC) screening was associated with lower risk of advanced neoplasia (AN). We evaluated whether prior FIT results should be included to estimate the risk of AN in 2008–2012.

Methods

A community-based screening practice recruited 5,813 asymptomatic residents aged 50 to 70 years in Hong Kong for CRC screening. We included study participants who had (1). positive FIT with subsequent colonoscopy workup (FIT+ group; n = 356); (2). negative FIT in three consecutive years and received a colonoscopy (FIT- group; n = 857); (3). received colonoscopy without FIT (colonoscopy group; n = 473); and (4). received both colonoscopy and FIT at the same time (combined group; n = 4,127). One binary logistic regression model evaluated whether prior FIT results were associated with colonoscopy findings of AN.

Results

The proportion of participants having AN/CRC was 18.0% (FIT+), 5.5% (FIT-), 8.0% (colonoscopy group), and 4.3% (combined group), respectively. When compared with the colonoscopy group, those in the FIT- group were not significantly more or less likely to have AN/CRC (AOR  = 0.77, 95% C.I. = 0.51 to 1.18, p  = 0.230). Having one (AOR = 0.73, 95% C.I. 0.48–1.12, p = 0.151) or three consecutive negative FIT result (AOR = 0.98, 95% C.I. 0.60–1.62, p = 0.944) were not associated with lower risks of AN/CRC. Subjects in the FIT+ group was 3.32-fold (95% C.I. 2.07 to 5.32, p<0.001) more likely to have AN/CRC.

Conclusions

These findings indicated that subjects with negative FIT findings could be risk stratified similarly as those who had not previously received FIT.     

Temporal and geographical variations in colorectal cancer incidence in Northern Iran 2004–2013

Introduction: Colorectal cancer (CRC) is one of the most common cancers in the Golestan province, Northern Iran. The purpose of this study is to describe colorectal cancer incidence patterns and trends in the province 2004–2013.Methods: Data on CRC cases were obtained from the Golestan Population-based Cancer Registry (GPCR). The GPCR is a high-quality cancer registry that collects data on primary cancers according to internationally accepted standard protocols. Age-standardized Incidence rates (ASR) were calculated and the 10-year trend quantified using the average annual percentage change (AAPC) from Joinpoint regressions.Results: The overall ASR of CRC were higher in men (14.8 per 100,000 person-years) and the urban populations (35.4), relative to women (11.5) and the rural populations (17.1), respectively. The overall incidence rate was observed to significantly increase 2004–2013 in men (AAPC = 7.3; 95%CI: 2.9–11.8) and women (AAPC = 6.6; 95%CI: 2.7–10.6). The analysis also showed that urban areas (AAPC = 8.1; 95%CI: 2.4–14.1) had a relatively more rapid increase in rates compared to rural areas (AAPC = 6.9; 95%CI: 2.2–11.7).Conclusions: CRC incidence rates in Golestan have been rising during the most recent decade, with a higher incidence and more rapid increases among men and the urban populations. The underlying risk factors should be assessed in the context of developing CRC prevention interventions in Golestan.     

Genetic variation in SLC7A2 interacts with calcium and magnesium intakes in modulating the risk of colorectal polyps

Solute carrier family 7, member 2 (SLC7A2) gene encodes a protein called cationic amino acid transporter 2, which mediates the transport of arginine, lysine and ornithine. l-Arginine is necessary for cancer development and progression, including an important role in colorectal cancer pathogenesis. Furthermore, previous studies found that both calcium and magnesium inhibit the transport of arginine. Thus, calcium, magnesium or calcium:magnesium intake ratio may interact with polymorphisms in the SLC7A2 gene in association with colorectal cancer. We conducted a two-phase case–control study within the Tennessee Colorectal Polyps Study. In the first phase, 23 tagging single-nucleotide polymorphisms in the SLC7A2 gene were included for 725 colorectal adenoma cases and 755 controls. In the second phase conducted in an independent set of 607 cases and 2113 controls, we replicated the significant findings in the first phase. We observed that rs2720574 significantly interacted with calcium:magnesium intake ratio in association with odds of adenoma, particularly multiple/advanced adenoma. In the combined analysis, among those with a calcium:magnesium intake ratio below 2.78, individuals who carried GC/CC genotypes demonstrated higher odds of adenoma [OR (95% CI):1.36 (1.11–1.68)] and multiple/advanced adenoma [OR (95% CI): 1.68 (1.28, 2.20)] than those who carried the GG genotype. The P values for interactions between calcium:magnesium intake ratio and rs2720574 were .002 for all adenomas and <.001 for multiple/advanced adenoma. Among those with the GG genotype, a high calcium:magnesium ratio was associated with increased odds of colorectal adenoma [OR (95% CI): 1.73 (1.27–2.36)] and advanced/multiple adenomas [1.62 (1.05–2.50)], whereas among those with the GC/CC genotypes, high calcium:magnesium ratio was related to reduced odds of colorectal adenoma [0.64 (0.42–0.99)] and advanced/multiple adenomas [0.55 (0.31–1.00)].     

Association between hypermethylation of DNA repetitive elements in white blood cell DNA and early-onset colorectal cancer

Changes in the methylation levels of DNA from white blood cells (WBCs) are putatively associated with an elevated risk for several cancers. The aim of this study was to investigate the association between colorectal cancer (CRC) and the methylation status of three DNA repetitive elements in DNA from peripheral blood. WBC DNA from 539 CRC cases diagnosed before 60 years of age and 242 sex and age frequency-matched healthy controls from the Australasian Colorectal Cancer Family Registry were assessed for methylation across DNA repetitive elements Alu, LINE-1 and Sat2 using MethyLight. The percentage of methylated reference (PMR) of cases and controls was calculated for each marker. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using multivariable logistic regression adjusted for potential confounders. CRC cases demonstrated a significantly higher median PMR for LINE-1 (p < 0.001), Sat2 (p < 0.001) and Alu repeats (p = 0.02) when compared with controls. For each of the DNA repetitive elements, individuals with PMR values in the highest quartile were significantly more likely to have CRC compared with those in the lowest quartile (LINE-1 OR = 2.34, 95%CI = 1.48–3.70; p < 0.001, Alu OR = 1.83, 95%CI = 1.17–2.86; p = 0.01, Sat2 OR = 1.72, 95%CI = 1.10–2.71; p = 0.02). When comparing the OR for the PMR of each marker across subgroups of CRC, only the Alu marker showed a significant difference in the 5-fluoruracil treated and nodal involvement subgroups (both p = 0.002). This association between increasing methylation levels of three DNA repetitive elements in WBC DNA and early-onset CRC is novel and may represent a potential epigenetic biomarker for early CRC detection.     

The polymorphisms in methylenetetrahydrofolate reductase, methionine synthase, methionine synthase reductase, and the risk of colorectal cancer

Polymorphisms in genes involved in folate metabolism may modulate the risk of colorectal cancer (CRC), but data from published studies are conflicting. The current meta-analysis was performed to address a more accurate estimation. A total of 41 (17,552 cases and 26,238 controls), 24(8,263 cases and 12,033 controls), 12(3,758 cases and 5,646 controls), and 13 (5,511 cases and 7,265 controls) studies were finally included for the association between methylenetetrahydrofolate reductase (MTHFR) C677T and A1289C, methione synthase reductase (MTRR) A66G, methionine synthase (MTR) A2756G polymorphisms and the risk of CRC, respectively. The data showed that the MTHFR 677T allele was significantly associated with reduced risk of CRC (OR = 0.93, 95%CI 0.90-0.96), while the MTRR 66G allele was significantly associated with increased risk of CRC (OR = 1.11, 95%CI 1.01-1.18). Sub-group analysis by ethnicity revealed that MTHFR C677T polymorphism was significantly associated with reduced risk of CRC in Asians (OR = 0.80, 95%CI 0.72-0.89) and Caucasians (OR = 0.84, 95%CI 0.76-0.93) in recessive genetic model, while the MTRR 66GG genotype was found to significantly increase the risk of CRC in Caucasians (GG vs. AA: OR = 1.18, 95%CI 1.03-1.36). No significant association was found between MTHFR A1298C and MTR A2756G polymorphisms and the risk of CRC. Cumulative meta-analysis showed no particular time trend existed in the summary estimate. Probability of publication bias was low across all comparisons illustrated by the funnel plots and Egger's test. Collectively, this meta-analysis suggested that MTHFR 677T allele might provide protection against CRC in worldwide populations, while MTRR 66G allele might increase the risk of CRC in Caucasians. Since potential confounders could not be ruled out completely, further studies were needed to confirm these results.     

Polymorphisms in methyl-group metabolism genes and risk of sporadic colorectal cancer with relation to the CpG island methylator phenotype

Background: The CpG island methylator phenotype (CIMP), together with extensive promoter methylation, is regarded as one of the mechanisms involved in colorectal carcinogenesis. The mechanisms underlying CIMP in sporadic colorectal cancer are poorly understood. Genes involved in methyl-group metabolism are likely to affect DNA methylation and thereby influence an individual's risk of CIMP. The aim of the present study was to evaluate whether polymorphisms in the genes encoding methyl-group metabolism pathway predispose to CIMP+ and/or CIMP? CRC. Methods: We examined the potential association between the polymorphisms of MTHFR 677C>T, TS 5′UTR 2R/3R, TS 3′UTR 1494del6, ΔDNMT3B ?149C>T and DNMT3B ?283T>C in a group of 46 CIMP+ CRC cases, 140 CIMP? CRC cases and 140 healthy controls. The CIMP status of the CRC cases was determined by MS-PCR in tumor tissue by a panel of five markers (CACNA1G, IGF2, NEUROG1, RUNX3 and SOCS1), which was also followed by analyzing hMLH1 methylation and BRAF V600E mutation. Results: The variant allele homozygote genotype for the ΔDNMT3B ?283T>C polymorphism was associated with a decreased risk for CIMP+ CRC (OR: 0.31, 95%CI: 0.09–0.73, p = 0.009). Individuals with TS 3R/3R had an increased risk of CIMP? CRC (OR: 2.21, 95%CI: 1.23–4.91, p = 0.01). Moreover, the carriers of 3R allele had an increased risk of CIMP? CRC (OR: 1.45, 95%CI: 1.10–2.13, p = 0.01). Conclusion: This study provides support to the hypothesis that methyl-group metabolism plays a role in the etiology of both CIMP+ and CIMP? colorectal cancers but has a different impact on a distinct molecular subgroups of colorectal cancer.