Meta-analysis of new genome-wide association studies of colorectal cancer risk

Colorectal cancer is the second leading cause of cancer death in developed countries. Genome-wide association studies (GWAS) have successfully identified novel susceptibility loci for colorectal cancer. To follow up on these findings, and try to identify novel colorectal cancer susceptibility loci, we present results for GWAS of colorectal cancer (2,906 cases, 3,416 controls) that have not previously published main associations. Specifically, we calculated odds ratios and 95% confidence intervals using log-additive models for each study. In order to improve our power to detect novel colorectal cancer susceptibility loci, we performed a meta-analysis combining the results across studies. We selected the most statistically significant single nucleotide polymorphisms (SNPs) for replication using ten independent studies (8,161 cases and 9,101 controls). We again used a meta-analysis to summarize results for the replication studies alone, and for a combined analysis of GWAS and replication studies. We measured ten SNPs previously identified in colorectal cancer susceptibility loci and found eight to be associated with colorectal cancer (p value range 0.02 to 1.8 × 10(-8)). When we excluded studies that have previously published on these SNPs, five SNPs remained significant at p < 0.05 in the combined analysis. No novel susceptibility loci were significant in the replication study after adjustment for multiple testing, and none reached genome-wide significance from a combined analysis of GWAS and replication. We observed marginally significant evidence for a second independent SNP in the BMP2 region at chromosomal location 20p12 (rs4813802; replication p value 0.03; combined p value 7.3 × 10(-5)). In a region on 5p33.15, which includes the coding regions of the TERT-CLPTM1L genes and has been identified in GWAS to be associated with susceptibility to at least seven other cancers, we observed a marginally significant association with rs2853668 (replication p value 0.03; combined p value 1.9 × 10(-4)). Our study suggests a complex nature of the contribution of common genetic variants to risk for colorectal cancer.

Interaction between alcohol drinking and obesity in relation to colorectal cancer risk: a case-control study in Newfoundland and Labrador, Canada

Background

While substantive epidemiological literature suggests that alcohol drinking and obesity are potential risk factors of colorectal cancer (CRC), the possible interaction between the two has not been adequately explored. We used a case-control study to examine if alcohol drinking is associated with an increased risk of CRC and if such risk differs in people with and without obesity.

Methods

Newly diagnosed CRC cases were identified between 1999 and 2003 in Newfoundland and Labrador (NL). Cases were frequency-matched by age and sex with controls selected using random digit dialing. Cases (702) and controls (717) completed self-administered questionnaires assessing health and lifestyle variables. Estimates of alcohol intake included types of beverage, years of drinking, and average number of alcohol drinks per day. Odds ratios were estimated to investigate the associations of alcohol independently and when stratified by obesity status on the risk of CRC.

Results

Among obese participants (BMI ≥ 30), alcohol was associated with higher risk of CRC (OR: 2.2; 95% CI: 1.2-4.0) relative to the non-alcohol category. Among obese individuals, 3 or more different types of drinks were associated with a 3.4-fold higher risk of CRC relative to non-drinkers. The risk of CRC also increased with drinking years and drinks daily among obese participants. However, no increased risk was observed in people without obesity.

Conclusion

The effect of alcohol of drinking on CRC seems to be modified by obesity.

Reported intake of selected micronutrients and risk of colorectal cancer: results from a large population-based case-control study in Newfoundland, Labrador and Ontario, Canada

AIM

The impact of micronutrient intake and colorectal cancer (CRC) risk is poorly understood. The objective of this study was to evaluate the associations of selected micronutrients with risk of incident CRC in study participants from Newfoundland, Labrador (NL) and Ontario (ON), Canada.

MATERIALS AND METHODS

We conducted a population-based study among 1760 case participants and 2481 age- and sex-matched control participants. Information on diet and other lifestyle factors were measured using a food frequency questionnaire and a personal history questionnaire. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using unconditional logistic regression, controlling for covariables.

RESULTS

Highest compared to lowest quartile intakes of certain micronutrients were associated with lower risk of CRC, including: calcium (from food and supplements (FS), OR=0.59; 95% CI=0.45-0.77, and from food only (FO): OR=0.76, 95% CI=0.59-0.97), vitamin C (FS:OR=0.67; 95%CI:0.51-0.88), vitamin D (FS: OR=0.73; 95% CI: 0.57-0.94, FO: OR=0.79, 95% CI=0.62-1.00), riboflavin (FS: OR=0.61; 95% CI=0.47-0.78, and folate (FS: OR=0.72; 95% CI=0.56-0.92). Higher risk of CRC was observed for iron intake (highest versus lowest quintiles: OR=1.34, 95% CI=1.01-1.78).

CONCLUSION

This study presents evidence that dietary intake of calcium, vitamin D, vitamin C, riboflavin and folate are associated with a lower risk of incident CRC and that dietary intake of iron may be associated with a higher risk of the disease.

Stroke in patients with type 2 diabetes mellitus, chronic kidney disease, and anemia treated with Darbepoetin Alfa: the trial to reduce cardiovascular events with Aranesp therapy (TREAT) experience

BACKGROUND

More strokes were observed in the Trial to Reduce Cardiovascular Events With Aranesp Therapy (TREAT) among patients assigned to darbepoetin alfa. We sought to identify baseline characteristics and postrandomization factors that might explain this association.

METHODS AND RESULTS

A multivariate logistic regression model was used to identify baseline predictors of stroke in 4038 patients with diabetes mellitus, chronic kidney disease, and anemia randomized to receive darbepoetin alfa or placebo. To determine whether postrandomization blood pressure, hemoglobin level, platelet count, or treatment dose were responsible for the increased risk related to darbepoetin alfa, we performed a nested case-control analysis (1:10 matching) identifying nonstroke controls with propensity matching. The risk of stroke was doubled with darbepoetin alfa. Overall, 154 patients had a stroke, 101/2012 (5.0%) in the darbepoetin alfa arm and 53/2026 (2.6%) in the placebo arm (hazard ratio 1.9; 95% confidence interval, 1.4-2.7). Independent predictors of stroke included assignment to darbepoetin alfa (odds ratio 2.1; 95% confidence interval, 1.5-2.9), history of stroke (odds ratio 2.0; 95% confidence interval, 1.4-2.9), more proteinuria, and known cardiovascular disease. In patients assigned to darbepoetin alfa, postrandomization systolic and diastolic blood pressure, hemoglobin level, platelet count, and darbepoetin alfa dose did not differ between those with and without stroke. Additional sensitivity analyses using maximal values, latest values, or changes over varying periods of exposure yielded similar results.

CONCLUSIONS

The 2-fold increase in stroke with darbepoetin alfa in TREAT could not be attributed to any baseline characteristic or to postrandomization blood pressure, hemoglobin, platelet count, or dose of treatment. These readily identifiable factors could not be used to mitigate the risk of darbepoetin alfa-related stroke.

CLINICAL TRIAL REGISTRATION

http://www.clinicaltrials.gov. Unique identifier: NCT00093015.

Impact of colonoscopic screening in male and female Lynch syndrome carriers with an MSH2 mutation

The lifetime risk of developing colorectal cancer (CRC) in Lynch syndrome (LS) carriers is very high. To determine the impact of colonoscopic screening in 54 male and 98 female MSH2 mutation carriers, outcomes were compared with 94 males and 76 females who were not screened. CRC incidence and survival in the screened group were compared to that expected, derived from the non-screened group. To correct for survivor bias, controls were matched for age at entry into screening and also for gender. In males, median age to CRC was 58 years, whereas expected was 47 years (p = 0.000), and median survival was 66 years vs 62 years (p = 0.034). In screened females, median age to CRC was 79 years compared to 57 years in the non-screened group (p = 0.000), and median survival was 80 years compared with expected of 63 years (p = 0.001). Twenty percent of males and 7% of females developed an interval CRC within 2 years of previous colonoscopy. Although colonoscopic screening was associated with decreased CRC risk and better survival, CRCs continued to occur. CRC development may be further reduced by decreasing the screening interval to 1 year and improving quality of colonoscopy.

Erythropoietin-stimulating agents in chronic kidney disease: a response to hyporesponsiveness

Hyporesponsiveness to erythropoietin stimulating agents occurs frequently, and may be observed at initiation of treatment or during maintenance therapy. An inverse relationship between hyporesponsiveness and incident cardiovascular events has been reported. It is related at least in part to co-morbidity and its occurrence requires a search for the cause. Treatment of anemia in hyporesponsive patients should be individualized, with consideration given to the indication for ESA therapy, the target hemoglobin for therapy, and maximal dose limitations.

The restructuring of institutional long-term care in St. John's: impact of supply-induced demand on planning

Restructuring of institutional long-term care was undertaken using predictions of future bed need with assumptions made on incidence rates of clients defined by type of disability, survival, and demographic changes. Recent substantial increase in the population rate of clients seeking placement across all degrees of disability, coincident with new facilities for those with modest disability, occurred. Consequently, more appropriate housing and supervised care beds, and more limited downsizing of nursing homes will be required.

Lynch syndrome: barriers to and facilitators of screening and disease management

Background

Lynch syndrome is a hereditary cancer with confirmed carriers at high risk for colorectal (CRC) and extracolonic cancers. The purpose of the current study was to develop a greater understanding of the factors influencing decisions about disease management post-genetic testing.

Methods

The study used a grounded theory approach to data collection and analysis as part of a multiphase project examining the psychosocial and behavioral impact of predictive DNA testing for Lynch syndrome. Individual and small group interviews were conducted with individuals from 10 families with the MSH2 intron 5 splice site mutation or exon 8 deletion. The data from confirmed carriers (n = 23) were subjected to re-analysis to identify key barriers to and/or facilitators of screening and disease management.

Results

Thematic analysis identified personal, health care provider and health care system factors as dominant barriers to and/or facilitators of managing Lynch syndrome. Person-centered factors reflect risk perceptions and decision-making, and enduring screening/disease management. The perceived knowledge and clinical management skills of health care providers also influenced participation in recommended protocols. The health care system barriers/facilitators are defined in terms of continuity of care and coordination of services among providers.

Conclusions

Individuals with Lynch syndrome often encounter multiple barriers to and facilitators of disease management that go beyond the individual to the provider and health care system levels. The current organization and implementation of health care services are inadequate. A coordinated system of local services capable of providing integrated, efficient health care and follow-up, populated by providers with knowledge of hereditary cancer, is necessary to maintain optimal health.

A nurse-coordinated model of care versus usual care for stage 3/4 chronic kidney disease in the community: a randomized controlled trial

BACKGROUND AND OBJECTIVES

It is unclear how to optimally care for chronic kidney disease (CKD). This study compares a new coordinated model to usual care for CKD.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A randomized trial in nephrology clinics and the community included 474 patients with median estimated GFR (eGFR) 42 ml/min per 1.73 m(2) identified by laboratory-based case finding compared care coordinated by a general practitioner (controls) with care by a nurse-coordinated team including a nephrologist (intervention) for a median (interquartile range [IQR]) of 742 days. 32% were diabetic, 60% had cardiovascular disease, and proteinuria was minimal. Guided by protocols, the intervention team targeted risk factors for adverse kidney and cardiovascular outcomes. Serial eGFR and clinical events were tracked.

RESULTS

The average decline in eGFR over 20 months was -1.9 ml/min per 1.73 m(2). eGFR declined by ≥4 ml/min per 1.73 m(2) within 20 months in 28 (17%) intervention patients versus 23 (13.9%) control patients. Control of BP, LDL, and diabetes were comparable across groups. In the intervention group there was a trend to greater use of renin-angiotensin blockers and more use of statins in those with initial LDL >2.5 mmol/L. Treatment was rarely required for anemia, acidosis, or disordered mineral metabolism. Clinical events occurred in 5.2% per year.

CONCLUSIONS

Patients with stage 3/4 CKD identified through community laboratories largely had nonprogressive kidney disease but had cardiovascular risk. Over a median of 24 months, the nurse-coordinated team did not affect rate of GFR decline or control of most risk factors compared with usual care.

Cost-effectiveness analysis of a randomized trial comparing care models for chronic kidney disease

BACKGROUND AND OBJECTIVES

Potential cost and effectiveness of a nephrologist/nurse-based multifaceted intervention for stage 3 to 4 chronic kidney disease are not known. This study examines the cost-effectiveness of a chronic disease management model for chronic kidney disease.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Cost and cost-effectiveness were prospectively gathered alongside a multicenter trial. The Canadian Prevention of Renal and Cardiovascular Endpoints Trial (CanPREVENT) randomized 236 patients to receive usual care (controls) and another 238 patients to multifaceted nurse/nephrologist-supported care that targeted factors associated with development of kidney and cardiovascular disease (intervention). Cost and outcomes over 2 years were examined to determine the incremental cost-effectiveness of the intervention. Base-case analysis included disease-related costs, and sensitivity analysis included all costs.

RESULTS

Consideration of all costs produced statistically significant differences. A lower number of days in hospital explained most of the cost difference. For both base-case and sensitivity analyses with all costs included, the intervention group required fewer resources and had higher quality of life. The direction of the results was unchanged to inclusion of various types of costs, consideration of payer or societal perspective, changes to the discount rate, and levels of GFR.

CONCLUSIONS

The nephrologist/nurse-based multifaceted intervention represents good value for money because it reduces costs without reducing quality of life for patients with chronic kidney disease.

Promoter methylation of Wnt5a is associated with microsatellite instability and BRAF V600E mutation in two large populations of colorectal cancer patients

Background:

In colorectal cancer (CRC), tumour microsatellite instability (MSI) status and CpG island methylator phenotype (CIMP) status are indicators of patient outcome, but the molecular events that give rise to these outcomes remain largely unknown. Wnt5a is a critical regulator of non-canonical Wnt activity and promoter hypermethylation of this gene has emerging prognostic roles in CRC; however the frequency and prognostic significance of this epigenetic event have not been explored in the context of colorectal tumour subtype. Consequently, we investigated the frequency and prognostic significance of Wnt5a methylation in a large cohort of MSI-stratified CRCs.

Methods:

Methylation was quantified in a large cohort of 1232 colorectal carcinomas from two clinically distinct populations from Canada. Associations were examined between methylation status and clinicopathlogical features, including tumour MSI status, BRAF V600E mutation, and patient survival.

Results:

In Ontario, Wnt5a methylation was strongly associated with MSI tumours after adjustment for age, sex, and tumour location (odds ratio (OR)=4.2, 95% confidence interval (CI)=2.4–7.4, P<10⁻⁶) and with BRAF V600E mutation, a marker of CIMP (OR=12.3, 95% CI=6.9–21.7, P<10⁻¹⁷), but was not associated with patient survival. Concordant results were obtained in Newfoundland.

Conclusion:

Methylation of Wnt5a is associated with distinct tumour subtypes, strengthening the evidence of an epigenetic-mediated Wnt bias in CRC.

Cancer risks for monoallelic MUTYH mutation carriers with a family history of colorectal cancer

Cancer risks for a person who has inherited a MUTYH mutation from only one parent (monoallelic mutation carrier) are uncertain. Using the Colon Cancer Family Registry and Newfoundland Familial Colon Cancer Registry, we identified 2,179 first- and second-degree relatives of 144 incident colorectal cancer (CRC) cases who were monoallelic or biallelic mutation carriers ascertained by sampling population complete cancer registries in the United States, Canada and Australia. Using Cox regression weighted to adjust for sampling on family history, we estimated that the country-, age- and sex-specific standardized incidence ratios (SIRs) for monoallelic mutation carriers, compared to the general population, were: 2.04 (95% confidence interval, CI 1.56-2.70; p < 0.001) for CRC, 3.24 (95%CI 2.18-4.98; p < 0.001) for gastric cancer, 3.09 (95%CI 1.07-12.25; p = 0.07) for liver cancer and 2.33 (95%CI 1.18-5.08; p = 0.02) for endometrial cancer. Age-specific cumulative risks to age 70 years, estimated using the SIRs and US population incidences, were: for CRC, 6% (95%CI 5-8%) for men and 4% (95%CI 3-6%) for women; for gastric cancer, 2% (95%CI 1-3%) for men and 0.7% (95%CI 0.5-1%) for women; for liver cancer, 1% (95%CI 0.3-3%) for men and 0.3% (95%CI 0.1-1%) for women and for endometrial cancer, 4% (95%CI 2-8%). There was no evidence of increased risks for cancers of the brain, pancreas, kidney, lung, breast or prostate. Monoallelic MUTYH mutation carriers with a family history of CRC, such as those identified from screening multiple-case CRC families, are at increased risk of colorectal, gastric, endometrial and possibly liver cancers.

Darbepoetin alfa impact on health status in diabetes patients with kidney disease: a randomized trial

BACKGROUND AND OBJECTIVES

Quality of life (QOL) is markedly impaired in patients with anemia, diabetes mellitus, and chronic kidney disease. Limited data exist regarding the effect of anemia treatment on patient perceptions. The objectives were to determine the longitudinal impact of anemia treatment on quality of life in patients with diabetes and chronic kidney disease and to determine the predictors of baseline and change in QOL.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In a large, double blind study, patients with type 2 diabetes mellitus, nondialysis chronic kidney disease (estimated GFR, 20 to 60 ml/min per 1.73 m(2)), and anemia (hemoglobin 10.4 g/dl) were randomized to darbepoetin alfa or placebo. QOL was measured with Functional Assessment of Cancer Therapy-Fatigue, Short Form-36, and EuroQol scores over 97 weeks.

RESULTS

Patients randomized to darbepoetin alfa reported significant improvements compared with placebo patients in Functional Assessment of Cancer Therapy-Fatigue, and EuroQol scores visual analog scores, persisting through 97 weeks. No consistent differences in Short Form-36 were noted. Consistent predictors of worse change scores include lower activity level, older age, pulmonary disease, and duration of diabetes. Interim stroke had a substantial negative impact on fatigue and physical function.

CONCLUSION

Darbepoetin alfa confers a consistent, but small, improvement in fatigue and overall quality of life but not in other domains. These modest QOL benefits must be considered in the context of neutral overall effect and increased risk of stroke in a small proportion of patients. Patient's QOL and potential treatment risk should be considered in any treatment decision.

Promoter methylation of Wnt antagonists DKK1 and SFRP1 is associated with opposing tumor subtypes in two large populations of colorectal cancer patients

Aberrant activation of canonical Wnt signaling is a hallmark event in colorectal carcinogenesis. The Dickkopf-1 (DKK1) and Secreted Frizzled Related Protein 1 (SFRP1) genes encode extracellular inhibitors of Wnt signaling that are frequently silenced by promoter hypermethylation in colorectal cancer (CRC). These methylation events have been identified as prognostic markers of patient outcome and tumor subtype in several cancers but similar roles in CRC have not been comprehensively examined. In CRC, the microsatellite instability (MSI) subtype associates with favorable disease outcome but the molecular events that are responsible remain poorly understood. Consequently, we quantified promoter methylation status of the Wnt antagonist genes DKK1 and SFRP1 in a large population-based cohort of CRCs from Ontario (n = 549) and Newfoundland (n = 696) stratified by MSI status. We examined the association between methylation status and clinicopathological features including tumor MSI status and patient survival. DKK1 and SFRP1 were methylated in 13 and 95% of CRCs, respectively. In Ontario, DKK1 methylation was strongly associated with MSI tumors after adjustment for age, sex and tumor location [odds ratio (OR) = 13.7, 95% confidence interval (CI) = 7.8-24.2, P < 0.001]. Conversely, SFRP1 methylation was inversely associated with MSI tumors after these adjustments (OR = 0.3, 95% CI = 0.1-0.9, P = 0.009). Similar results were obtained in Newfoundland. There were no independent associations with recurrence-free survival. This is the first large study to identify associations between Wnt antagonist promoter hypermethylation and CRC MSI subtype. These events provide insight into subtype-specific epigenetic mediation of Wnt signaling in CRC.

Tobacco smoking and colorectal cancer: a population-based case-control study in Newfoundland and Labrador

OBJECTIVE

Newfoundland and Labrador (NL) has the highest incidence rate of both colorectal cancer (CRC) and smoking prevalence in Canada. The objective of this study was to examine if CRC is associated with smoking in this population.

METHODS

Newly diagnosed cases identified between 1999 and 2003 were frequency-matched by 5-year age group and sex with controls selected from the residents of NL through random digit dialing. A total of 702 cases and 717 controls consented to participate in the study and completed a set of self-administered questionnaires. Measures of tobacco use included type of tobacco, age of initiation of smoking, years of smoking, years since started smoking, number of cigarettes smoked daily, pack years, and years since abstention from smoking. Odds ratios were estimated using multivariate logistic regression.

RESULTS

In comparison with non-smokers, former and current smokers were at a significantly elevated risk of CRC with corresponding odds ratios of 1.36 and 1.96. The risk significantly increased with cigarette smoking years, the amount of cigarettes smoked daily, and cigarette pack years. The risk significantly decreased with years of abstention from smoking cigarettes. This association was stronger among drinkers and in men. In addition, this effect was observed to be slightly stronger for rectum than colon cancer.

DISCUSSION

In summary, cigarette smoking increased the risk of CRC in the NL population. The risk of CRC associated with cigarette smoking varies by sex, drinking status, and site of CRC.

Specific variants in the MLH1 gene region may drive DNA methylation, loss of protein expression, and MSI-H colorectal cancer

BACKGROUND

We previously identified an association between a mismatch repair gene, MLH1, promoter SNP (rs1800734) and microsatellite unstable (MSI-H) colorectal cancers (CRCs) in two samples. The current study expanded on this finding as we explored the genetic basis of DNA methylation in this region of chromosome 3. We hypothesized that specific polymorphisms in the MLH1 gene region predispose it to DNA methylation, resulting in the loss of MLH1 gene expression, mismatch-repair function, and consequently to genome-wide microsatellite instability.

METHODOLOGY/PRINCIPAL FINDINGS

We first tested our hypothesis in one sample from Ontario (901 cases, 1,097 controls) and replicated major findings in two additional samples from Newfoundland and Labrador (479 cases, 336 controls) and from Seattle (591 cases, 629 controls). Logistic regression was used to test for association between SNPs in the region of MLH1 and CRC, MSI-H CRC, MLH1 gene expression in CRC, and DNA methylation in CRC. The association between rs1800734 and MSI-H CRCs, previously reported in Ontario and Newfoundland, was replicated in the Seattle sample. Two additional SNPs, in strong linkage disequilibrium with rs1800734, showed strong associations with MLH1 promoter methylation, loss of MLH1 protein, and MSI-H CRC in all three samples. The logistic regression model of MSI-H CRC that included MLH1-promoter-methylation status and MLH1 immunohistochemistry status fit most parsimoniously in all three samples combined. When rs1800734 was added to this model, its effect was not statistically significant (P-value  = 0.72 vs. 2.3×10(-4) when the SNP was examined alone).

CONCLUSIONS/SIGNIFICANCE

The observed association of rs1800734 with MSI-H CRC occurs through its effect on the MLH1 promoter methylation, MLH1 IHC deficiency, or both.

The genetic basis of colorectal cancer in a population-based incident cohort with a high rate of familial disease

BACKGROUND AND AIMS

Colorectal cancer (CRC) is the second most frequent cancer in developed countries. Newfoundland has the highest incidence of CRC in Canada and the highest rate of familial CRC yet reported in the world. To determine the impact of mutations in known CRC susceptibility genes and the contribution of the known pathways to the development of hereditary CRC, an incident cohort of 750 patients with CRC (708 different families) from the Newfoundland population was studied.

METHODS

Microsatellite instability (MSI) testing was performed on tumours, together with immunohistochemistry analysis for mismatch repair (MMR) genes. Where indicated, DNA sequencing and multiplex ligation-dependent probe amplifications of MMR genes and APC was undertaken. DNA from all patients was screened for MUTYH mutations. The presence of the BRAF variant, p.V600E, and of MLH1 promoter methylation was also tested in tumours.

RESULTS

4.6% of patients fulfilled the Amsterdam criteria (AC), and an additional 44.6% fulfilled the revised Bethesda criteria. MSI-high (MSI-H) was observed in 10.7% (n=78) of 732 tumours. In 3.6% (n=27) of patients, CRC was attributed to 12 different inherited mutations in six known CRC-related genes associated with chromosomal instability or MSI pathways. Seven patients (0.9%) carried a mutation in APC or biallelic mutations in MUTYH. Of 20 patients (2.7%) with mutations in MMR genes, 14 (70%) had one of two MSH2 founder mutations. 17 of 28 (61%) AC families did not have a genetic cause identified, of which 15 kindreds fulfilled the criteria for familial CRC type X (FCCTX).

CONCLUSIONS

Founder mutations accounted for only 2.1% of cases and this was insufficient to explain the high rate of familial CRC. Many of the families classified as FCCTX may have highly penetrant mutations segregating in a Mendelian-like manner. These families will be important for identifying additional CRC susceptibility loci.

Increased cancer predisposition in family members of colorectal cancer patients harboring the p.V600E BRAF mutation: a population-based study

BACKGROUND

The serrated pathway represents a distinct molecular pathway of colorectal carcinogenesis and is associated with the p.V600E BRAF mutation. The objective of this study is to characterize the cancer family history and clinicopathologic features of colorectal cancer (CRC) patients according to the microsatellite instability (MSI) and BRAF mutation status of their tumors.

METHODS

The tumors from 558 population-based CRC patients underwent pathologic examination and molecular analysis for MSI, BRAF, and germline mutations in mismatch repair genes MUTYH and APC. The cancer history in first-degree relatives (FDR) of index patients was ascertained.

RESULTS

The risk of CRC in FDRs of index patients with MSI-H BRAF mutation [hazard ratio (HR) = 2.49; 95% confidence interval (95% CI), 1.57- 3.93] and microsatellite-stable BRAF mutation tumors (HR = 1.64; 95% CI, 1.01-2.66) was significantly elevated compared with FDRs of index patients with microsatellite-stable BRAF wild-type tumors. The incidence of nonmelanoma skin cancer was also significantly elevated in FDRs of patients with BRAF mutation CRC (HR = 2.52; 95% CI, 1.31-4.86). Furthermore, BRAF mutation CRC was associated with a distinct clinical, molecular, and pathologic phenotype.

CONCLUSIONS

The increased incidence of cancer in FDRs of index CRC patients with the p.V600E BRAF mutation may be explained by a genetic predisposition to develop cancer through the serrated pathway of colorectal carcinogenesis.

IMPACT

Family members of BRAF CRC patients have an increased predisposition to develop cancer. Future work should aim to identify the causative genetic factors.

Pickled meat consumption and colorectal cancer (CRC): a case-control study in Newfoundland and Labrador, Canada

OBJECTIVE

Although a large body of epidemiological research suggests that red meat intake increases the risk of colorectal cancer, little is known regarding how such an association varies across populations and types of red meat. The objective of this study was to assess whether an association exists between the intakes of total red meat and pickled red meat and the risk of colorectal cancer in study subjects residing in Newfoundland and Labrador.

METHODS

This case-control study of 1,204 residents of Newfoundland and Labrador was part of a larger study on colorectal cancer. Personal history food frequency questionnaires were used to collect retrospective data from 518 individuals diagnosed with colorectal cancer and 686 controls. Intakes were ranked and divided into tertiles. Logistic regression was used to examine the possible association between meat intakes and colorectal cancer diagnosis while controlling for possible confounding factors.

RESULTS

A positive, but non-statistically significant, association between total red meat intake and CRC was observed in this study. Pickled red meat consumption was found to be significantly associated with an increased risk of CRC (men, OR = 2.07, 95% CI 1.37-3.15; women, OR = 2.51, 95% CI 1.45-4.32), the odds ratios increasing with each tertile of consumption, suggesting a dose-response effect.

CONCLUSION

Intake of pickled red meat appears to increase the risk of colorectal cancer in Newfoundland and Labrador.

Left ventricular hypertrophy in new hemodialysis patients without symptomatic cardiac disease

BACKGROUND AND OBJECTIVES

Although left ventricular hypertrophy (LVH) is a characteristic finding in hemodialysis (HD) populations, few risk factors for progressive LVH have been identified.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

As part of a multinational, blinded, randomized, controlled trial that demonstrated no effect of hemoglobin targets on LV size, 596 incident HD patients, without symptomatic cardiac disease or cardiac dilation, had baseline echocardiograms within 18 months of starting dialysis and subsequently at 24, 48, and 96 weeks later. A wide array of baseline risk factors were assessed, as were BP and hemoglobin levels during the trial.

RESULTS

The median age and duration of dialysis were 51.5 years and 9 months, respectively. LV mass index (LVMI) rose substantially during follow-up (114.2 g/m(2) at baseline, 121 at week 48, 123.4 at week 48, and 128.3 at week 96), as did fractional shortening, whereas LV volume (68.7, 70.1, 68.7, and 68.1 ml/m(2)) and E/A ratio remained unchanged. At baseline, the only multivariate associations of LVMI were gender and N terminal pro-B type natriuretic peptide. Comparing first and last echocardiograms in those without LVH at baseline, independent predictors of increase in LVMI were higher time-integrated systolic BP and cause of ESRD. An unadjusted association between baseline LVMI and subsequent cardiovascular events or death was eliminated by adjusting for age, diabetes, systolic BP, and N terminal pro-B type natriuretic peptide.

CONCLUSIONS

Progressive concentric LVH and hyperkinesis occur in HD patients, which is partly explained by hypertension but not by a wide array of potential risk factors, including anemia.

The breast cancer hormone receptor retesting controversy in Newfoundland and Labrador, Canada: lessons for the health system

The treatment of newly diagnosed breast cancer patients with hormonal treatment is determined by the presence of estrogen receptor and progesterone receptor status in breast cancer. In Newfoundland and Labrador (NL), 425 of 1088 (39.1%) patients who had original "negative" receptor tests conducted between 1997 and 2005, had positive results upon retesting in a specialized laboratory. This commentary addresses (1) the diagnostic utility of estrogen and progesterone testing for breast cancer in general, (2) specific testing problems that occurred in NL, (3) scientific problems associated with retesting, and (4) the impact on public trust and the resulting legal and political responses that occurred as a result of the adverse events associated with false-negative hormone receptor tests. Finally, the lessons learned will be discussed including known high false-negative rates associated with the tests and the bias associated with retesting, the need for quality assurance and national standards, public education, and appropriate communication with patients and the public.