Identification and monitoring of metabolite markers of dry bean consumption in parallel human and mouse studies.

Scope: Aim of the study was to identify and monitor metabolite markers of dry bean consumption in parallel human and mouse studies that each had shown chemopreventive effects of dry bean consumption on colorectal neoplasia risk.

Methods And Results: Using LC/mass spectroscopy ± ESI and GC/mass spectroscopy, serum metabolites of dry beans were measured in 46 men before and after a 4-week dry bean enriched diet (250 g/day) and 12 mice that received a standardized diet containing either 0 or 10% navy bean ethanol extract for 6 weeks; we also investigated fecal metabolites in the mice. The serum metabolites identified in these controlled feeding studies were then investigated in 212 polyp-free participants from the Polyp Prevention Trial who self-reported either increased (≥+31 g/day from baseline), high dry bean intake of ≥42 g/day in year 3 or low, unchanged dry bean consumption of <8 g/day; serum was analyzed from baseline and year 3.

Factors associated with the risk of adenoma recurrence in distal and proximal colon.

Background/aims: Colonoscopy may be less effective in preventing cancer in the proximal colon. We evaluated whether risk factors for adenoma recurrence exhibit differential effect on adenoma recurrence by colon subsite.

Methods: We examined the association of age, sex, body mass index, smoking status and use of nonsteroidal anti-inflammatory drugs (NSAIDs) on proximal and distal adenoma recurrence among 1,864 participants in the Polyp Prevention Trial.

Short- and long-term risk of colorectal adenoma recurrence among whites and blacks.

Background: It is unclear whether the higher burden from colorectal cancer among blacks is due to an increased biological susceptibility.

Objective: To determine whether non-Hispanic blacks (blacks) have a higher risk of adenoma recurrence than non-Hispanic whites (whites) after removal of colorectal adenoma.

Design: Secondary analysis of the Polyp Prevention Trial (PPT) data.

Serum macrophage inhibitory cytokine-1 (MIC-1/GDF15): a potential screening tool for the prevention of colon cancer?

Background: Macrophage inhibitory cytokine-1 (MIC-1/GDF15) mediates nonsteroidal anti-inflammatory drug (NSAID) protection from colonic polyps in mice and is linked to the development of colorectal carcinoma in humans. Therefore, changes in serum MIC-1/GDF15 levels could predict the presence of premalignant colonic polyposis and assist in population screening strategies.

Methods: Serum MIC-1/GDF15 levels were measured in subjects in the Polyp Prevention Trial, in which NSAID use and colon cancer risk factors were defined.

Dietary lignan and proanthocyanidin consumption and colorectal adenoma recurrence in the Polyp Prevention Trial.

Lignans and proanthocyanidins are plant polyphenols that have shown protective properties against colorectal neoplasms in some human studies. Using logistic regression, we estimated odds ratios (ORs) and 95% confidence intervals (CIs) to prospectively evaluate the association between lignan and proanthocyanidin intake, estimated from databases linked to a food frequency questionnaire, and adenoma recurrence in 1,859 participants of the Polyp Prevention Trial. Overall, individual or total lignans or proanthocyanidins were not associated with colorectal adenoma recurrence.

Likelihood of missed and recurrent adenomas in the proximal versus the distal colon.

Background: Colonoscopy may be less efficacious in reducing colorectal cancer mortality in the proximal compared with the distal colon. A greater likelihood for missed and recurrent adenomas in the proximal colon may contribute to this phenomenon.

Objective: To examine whether a proximal adenoma is associated with the risk and location of missed and recurrent adenomas.

Do interleukin polymorphisms play a role in the prevention of colorectal adenoma recurrence by dietary flavonols?

Chemopreventive dietary compounds, such as flavonols, may inhibit colorectal carcinogenesis partly by altering cytokine expression and attenuating inflammation. Single nucleotide polymorphisms (SNPs) in the promoter regions of genes encoding cytokines may influence flavonol-induced changes in cytokine expression and consequently cancer risk. Using logistic regression, we estimated odds ratios (OR) and 95% confidence intervals (CI) for the association between SNPs of interleukin (IL)-1β, 6, 8, and 10 alone or combined with flavonol intake or serum IL concentration changes, and adenoma recurrence in 808 participants from the intervention arm of the Polyp Prevention Trial, a 4-year intervention study evaluating the effectiveness of a low-fat, high-fiber, high-fruit and vegetable diet on adenoma recurrence.

A high legume low glycemic index diet improves serum lipid profiles in men.

Clinical studies have shown that fiber consumption facilitates weight loss and improves lipid profiles; however, the beneficial effects of high fermentable fiber low glycemic index (GI) diets under conditions of weight maintenance are unclear. In the Legume Inflammation Feeding Experiment, a randomized controlled cross-over feeding study, 64 middle-aged men who had undergone colonoscopies within the previous 2 years received both a healthy American (HA) diet (no legume consumption, fiber consumption = 9 g/1,000 kcal, and GI = 69) and a legume enriched (1.5 servings/1,000 kcal), high fiber (21 g/1,000 kcal), low GI (GI = 38) diet (LG) in random order.

Serum adiponectin, leptin, C-peptide, homocysteine, and colorectal adenoma recurrence in the Polyp Prevention Trial.

Background: Serum adiponectin, leptin, C-peptide, and homocysteine are indicators for obesity, hyperinsulinemia, and chronic inflammation, which have all been associated with colorectal cancer.

Aims: To determine whether serum adiponectin, leptin, C-peptide, and homocysteine are associated with fat, fiber, fruit and vegetable, flavonol, or dry bean intake and colorectal adenoma recurrence.

Methods: Using logistic regression, we estimated odds ratios (OR) and 95% confidence intervals (95% CI) for adenoma recurrence in 627 participants from the control arm of the Polyp Prevention Trial, a 4-year trial that examined the effectiveness of a low-fat, high-fiber, high-fruit and vegetable diet on adenoma recurrence.

Interleukin-6 as a potential indicator for prevention of high-risk adenoma recurrence by dietary flavonols in the polyp prevention trial.

Serum interleukin-6 (IL-6), a proinflammatory cytokine, is considered an indicator of inflammation and may be an indicator of colorectal carcinogenesis given that inflammation can promote carcinogenesis. Flavonols, which can be found in fruits and vegetables, may inhibit colorectal carcinogenesis partly by inhibiting inflammation. We estimated odds ratios and 95% confidence intervals (95% CI) to determine whether serum IL-6 was associated with colorectal adenoma recurrence and flavonol intake and thus may serve as a risk indicator and as a response indicator to dietary flavonols.

Consumption of a legume-enriched, low-glycemic index diet is associated with biomarkers of insulin resistance and inflammation among men at risk for colorectal cancer.

The Legume Inflammation Feeding Experiment is, to our knowledge, the first randomized crossover feeding trial testing the effects of a legume-enriched, low-glycemic index (GI) diet among men characterized for colorectal adenomas and insulin resistance (IR) status. This study was designed to test the effects of a legume-enriched diet compared with a healthy American (HA) diet under weight-stable conditions. The primary objective was to assess effects on C-reactive protein (CRP) and C-peptide levels.

Ongoing colorectal cancer risk despite surveillance colonoscopy: the Polyp Prevention Trial Continued Follow-up Study.

Background: Despite regular colonoscopy, interval colorectal cancer (CRC) may occur. Long-term studies examining CRC rates in patients with previous colonoscopy are lacking.

Objective: We examined the rate of interval CRC in the Polyp Prevention Trial Continued Follow-up Study (PPT-CFS), an observational study of PPT participants that began after the PPT ended.

The effect of strict adherence to a high-fiber, high-fruit and -vegetable, and low-fat eating pattern on adenoma recurrence.

Individual differences in dietary intake are thought to account for substantial variation in cancer incidence. However, there has been a consistent lack of effect for low-fat, high-fiber dietary interventions and risk of colorectal cancer. These inconsistencies may reflect the multistage process of cancer as well as the range and timing of dietary change.

Noninvasive detection of candidate molecular biomarkers in subjects with a history of insulin resistance and colorectal adenomas.

We have developed novel molecular methods using a stool sample, which contains intact sloughed colon cells, to quantify colonic gene expression profiles. In this study, our goal was to identify diagnostic gene sets (combinations) for the noninvasive classification of different phenotypes. For this purpose, the effects of a legume-enriched, low glycemic index, high fermentable fiber diet was evaluated in subjects with four possible combinations of risk factors, including insulin resistance and a history of adenomatous polyps.

A pooled analysis of advanced colorectal neoplasia diagnoses after colonoscopic polypectomy.

Background & Aims: Limited data exist regarding the actual risk of developing advanced adenomas and cancer after polypectomy or the factors that determine risk.

Methods: We pooled individual data from 8 prospective studies comprising 9167 men and women aged 22 to 80 with previously resected colorectal adenomas to quantify their risk of developing subsequent advanced adenoma or cancer as well as identify factors associated with the development of advanced colorectal neoplasms during surveillance.

Results: During a median follow-up period of 47.

Inflammation-associated serum and colon markers as indicators of dietary attenuation of colon carcinogenesis in ob/ob mice.

Although inflammatory cytokines and obesity-associated serum proteins have been reported as biomarkers of colorectal adenoma risk in humans, little is known of biomarkers of response to interventions that attenuate tumorigenesis. Dietary navy beans and their fractions attenuate colon carcinogenesis in carcinogen-induced genetically obese mice. We hypothesized that this attenuation would be associated with changes in inflammatory cytokines and obesity-related serum proteins that may serve as measures of efficacy.

Utilization and yield of surveillance colonoscopy in the continued follow-up study of the polyp prevention trial.

Background And Aims: Prospective information on the use and yield of surveillance colonoscopy is limited. We examined the use and yield of surveillance colonoscopy among participants in the Polyp Prevention Trial (PPT) after the 4-year dietary intervention trial ended.

Methods: We followed a cohort of 1297 participants.

Dopamine D2 receptor polymorphisms and adenoma recurrence in the Polyp Prevention Trial.

Epidemiological evidence suggests that obesity may be causally associated with colorectal cancer. Dopamine and the dopaminergic reward pathway have been implicated in drug and alcohol addiction as well as obesity. Polymorphisms within the D2 dopamine receptor gene (DRD2) have been shown to be associated with colorectal cancer risk.

Hyperplastic polyps and the risk of adenoma recurrence in the polyp prevention trial.

Background And Aims: Recent studies have suggested that some hyperplastic polyps may be associated with an increased risk of colorectal cancer. Prospective information on the risk of adenoma recurrence associated with hyperplastic polyps is limited. We sought to investigate whether the coexistence of hyperplastic polyps with adenomas increases the risk of adenoma recurrence.

Serum concentrations of insulin-like growth factor and insulin-like growth factor binding protein 3 and recurrent colorectal adenomas.

Insulin-like growth factor I (IGF-I) and its primary binding protein, IGFBP-3, have been associated with colorectal cancer incidence in prior epidemiologic studies. High concentrations of IGF-I generally result in increasing risk and high concentrations of IGFBP-3 in decreasing risk. Only one prior study of IGF-I and IGFBP-3 and adenoma recurrence has been reported.

Dietary flavonoids and colorectal adenoma recurrence in the Polyp Prevention Trial.

Two recent case-control studies suggested that some flavonoid subgroups may play a role in preventing colorectal cancer. Previous prospective cohort studies generally reported no association; however, only a small subset of flavonoids was evaluated and partial flavonoid databases were used. We used the newly constructed U.

Dietary cooked navy beans and their fractions attenuate colon carcinogenesis in azoxymethane-induced ob/ob mice.

Based on the protective effects of cooked dry bean consumption in a human intervention study, we evaluated which fraction of cooked dry beans is responsible for its cancer-preventive effects. Cooked navy beans (whole beans), the insoluble fraction (bean residue) or soluble fraction of the 60% (vol:vol) ethanol extract of cooked navy beans (bean extract), or a modified AIN-93G diet (16.6% fat including 12.

Polynucleotide kinase 3' phosphatase variant, dietary variables and risk of adenoma recurrence in the Polyp Prevention Trial.

Polymorphisms in a number of genes encoding for DNA repair enzymes have been associated with altering the function of these enzymes and increasing risk of a number of cancers, including colon cancer. We have investigated the association between a common variant in polynucleotide kinase 3' phosphatase (PNKP), a putative DNA repair enzyme, and risk of adenoma recurrence in the Polyp Prevention Trial participants. We also investigated possible interaction or effect modification between carriage of the variant allele, dietary components and risk of adenoma recurrence.

Postpolypectomy colonoscopy surveillance guidelines: predictive accuracy for advanced adenoma at 4 years.

Background: Lack of confidence in postpolypectomy surveillance guidelines may be a factor in the observed low adherence rates among providers.

Objective: To assess the 2006 postpolypectomy colonoscopy surveillance guidelines, which recommend 3-year follow-up colonoscopy for individuals with high-risk adenomas (defined as > or =3 adenomas or any advanced adenomas) and 5- to 10-year follow-up for patients with 2 or fewer nonadvanced adenomas, who are considered to be at low risk.

Design: Analysis of prospective data from the Polyp Prevention Trial.

Folate and MTHFR: risk of adenoma recurrence in the Polyp Prevention Trial.

Background: Low dietary folate intake has been associated with colorectal cancer risk and adenoma recurrence. A C/T transition at position 677 in the gene encoding methlylenetetrahydrofolate reductase (MTHFR C677T) has been reported to interact with folate intake to modulate colorectal adenoma recurrence or cancer risk.

Methods: We investigated the association between MTHFR, total folate, and the risk of colorectal adenoma recurrence in the Polyp Prevention Trial.