Energy balance-related factors in childhood and adolescence and risk of colorectal cancer expressing different levels of proteins involved in the Warburg-effect.

Early-life (childhood to adolescence) energy balance-related factors (height, energy restriction, BMI) have been associated with adult colorectal cancer (CRC) risk. Warburg-effect activation via PI3K/Akt-signaling might explain this link. We investigated whether early-life energy balance-related factors were associated with risk of Warburg-subtypes in CRC. We used immunohistochemistry for six proteins involved in the Warburg-effect (LDHA, GLUT1, MCT4, PKM2, P53, and PTEN) on tissue microarrays of 2399 incident CRC cases from the prospective Netherlands Cohort Study (NLCS). Expression levels of all proteins were combined into a pathway-based sum score and categorized into three Warburg-subtypes (Warburg-low/-moderate/-high). Multivariable Cox-regression analyses were used to estimate associations of height, energy restriction proxies (exposure to Dutch Hunger Winter; Second World War [WWII]; Economic Depression) and adolescent BMI with Warburg-subtypes in CRC. Height was positively associated with colon cancer in men, regardless of Warburg-subtypes, and with Warburg-low colon and Warburg-moderate rectal cancer in women. Energy restriction during the Dutch Hunger Winter was inversely associated with colon cancer in men, regardless of Warburg-subtypes. In women, energy restriction during the Hunger Winter and WWII was inversely associated with Warburg-low colon cancer, whereas energy restriction during the Economic Depression was positively associated with Warburg-high colon cancer. Adolescent BMI was positively associated with Warburg-high colon cancer in men, and Warburg-moderate rectal cancer in women. In conclusion, the Warburg-effect seems to be involved in associations of adolescent BMI with colon cancer in men, and of energy restriction during the Economic Depression with colon cancer in women. Further research is needed to validate these results.

Empirical Investigation of Genomic Clusters Associated With Height and the Risk of Postmenopausal Breast and Colorectal Cancer in the Netherlands Cohort Study.

We empirically investigated genomic clusters associated with both height and postmenopausal breast cancer (BC) or colorectal cancer (CRC) (or both) in the Netherlands Cohort Study to unravel shared underlying mechanisms between height and these cancers. The Netherlands Cohort Study (1986-2006) includes 120,852 participants (case-cohort study: nsubcohort = 5,000; 20.3 years of follow-up). Variants in clusters on chromosomes 2, 4, 5, 6 (2 clusters), 10, and 20 were genotyped using toenail DNA. Cluster-specific genetic risk scores were modeled in relation to height and postmenopausal BC and CRC risk using age-adjusted linear regression and multivariable-adjusted Cox regression, respectively. Only the chromosome 10 cluster risk score was associated with all 3 phenotypes in the same sex (women); that is, it was associated with increased height (ßcontinuous = 0.34, P = 0.014), increased risk of hormone-receptor-positive BC (for estrogen-receptor-positive BC, hazard ratio (HRcontinuous score) = 1.10 (95% confidence interval (CI): 1.02, 1.20); for progesterone-receptor-positive BC, HRcontinuous score = 1.15 (95% CI: 1.04, 1.26)), and increased risk of distal colon (HRcontinuous score = 1.13, 95% CI: 1.01, 1.27) and rectal (HRcontinuous score = 1.14, 95% CI: 0.99, 1.30) cancer. The chromosome 10 cluster variants were all annotated to the zinc finger MIZ-type containing 1 gene (ZMIZ1), which is involved in androgen receptor activity. This suggests that hormone-related growth mechanisms could influence both height and postmenopausal BC and CRC.

Energy balance-related factors in childhood and adolescence and risk of colorectal cancer based on KRAS, PIK3CA, and BRAF mutations and MMR status.

KRAS mutations (KRASmut ), PIK3CAmut , BRAFmut , and deficient DNA mismatch repair (dMMR) have been associated with the Warburg effect. We previously reported differential associations between early-life energy balance-related factors (height, energy restriction, body mass index [BMI]) and colorectal cancer (CRC) subtypes based on the Warburg effect. We now investigated associations of early-life energy balance-related factors and the risk of CRC subgroups based on mutation and MMR status. Data from the Netherlands Cohort Study was used. KRASmut , PIK3CAmut, BRAFmut, and MMR status were available for 2349 CRC cases, and complete covariate data for 1934 cases and 3911 subcohort members. Multivariable-adjusted Cox regression was used to estimate associations of height, energy restriction proxies (exposure to Dutch Hunger Winter, Second World War, Economic Depression), and early adult BMI (age 20 years) with risk of CRC based on individual molecular features and combinations thereof (all-wild-type+MMR-proficient [pMMR]; any-mutation/dMMR). Height was positively associated with any-mutation/dMMR CRC but not all-wild-type+pMMR CRC, with the exception of rectal cancer in men, and with heterogeneity in associations observed for colon cancer in men (p-heterogeneity = 0.049) and rectal cancer in women (p-heterogeneity = 0.014). Results on early-life energy restriction proxies in relation to the risk of CRC subgroups did not show clear patterns. Early adult BMI was positively, but not significantly, associated with KRASmut colon cancer in men and with BRAFmut and dMMR colon cancer in women. Our results suggest a role of KRASmut , PIK3CAmut , BRAFmut , and dMMR in the etiological pathway between height and CRC risk. KRASmut might potentially play a role in associations of early adult BMI with colon cancer risk in men, and BRAFmut and dMMR in women.

Nut and peanut butter intake and the risk of colorectal cancer and its anatomical and molecular subtypes: the Netherlands Cohort Study.

Nut intake has been associated with reduced total cancer-related mortality, but evidence for colorectal cancer (CRC) risk is inconclusive. We investigated the associations between nut and peanut butter intake and anatomical CRC subtypes. To account for molecular heterogeneity, associations between nut and peanut butter intake and colorectal tumors harboring APC, KRAS or BRAF mutations, p53 overexpression or microsatellite instability were examined in secondary analyses. In the Netherlands Cohort Study (n = 120 852), lifestyle habits were measured with a questionnaire in 1986. After 20.3 years follow-up, 3567 CRC cases were included in case-cohort analyses. For the analyses of molecular CRC subtypes, 574 cases were included after 7.3 years follow-up. In categorical analyses, total nut intake was not significantly associated with CRC [HR (95% CI) 10+ g/day versus non-consumers = 0.94(0.78-1.15) in men; 0.96(0.75-1.22) in women]. In restricted cubic spline analyses, significant non-linear inverse associations with rectal cancer were observed for total nut, peanut and peanut butter intake in women, and borderline significant non-linear inverse associations for total nut and peanut intake in men. Regarding the molecular CRC subtypes, peanut butter intake was significantly associated with an increased risk of colorectal tumors that did not develop through the serrated neoplasia pathway in men [HR (95% CI) per 5 g/day increment = 1.22(1.07-1.38)]. Nut and peanut butter intake are non-linearly inversely associated with rectal cancer risk in women. In men, nut intake is borderline significantly non-linearly associated with a reduced rectal cancer risk. Peanut butter is associated with an increased risk of colorectal tumors that do not develop through the serrated neoplasia pathway in men.

Diabetes mellitus, genetic variants in the insulin-like growth factor pathway and colorectal cancer risk.

Genetic variation in the insulin-like growth factor (IGF) pathway may further increase the risk of colorectal cancer (CRC) associated with type 2 diabetes mellitus (T2DM). Joint effects of T2DM and genetic variation in the IGF pathway on CRC risk can increase mechanistic insights. Participants from the Netherlands Cohort Study (n = 120, 852) completed a baseline questionnaire in 1986 when 55-69 years old (case-cohort, nsubcohort = 5,000, ncases = 3,441 after 16.3 years follow-up). Self-reported DM at baseline with onset at ≥30 years was classified as T2DM. Eighteen single nucleotide polymorphisms (SNPs) from the IGF pathway were aggregated in a genetic risk score (GRS). Cox proportional hazard ratios (HRs) for CRC were estimated according to combinations of T2DM status with GRS tertiles and categories of an IGF1 19-CA repeat polymorphism. Baseline T2DM prevalence was 3.1% in subcohort members and 3.8% in CRC cases. Comparison of combined categories with non-T2DM individuals in the lowest GRS tertile as reference showed that those in the highest GRS tertiles with and without T2DM had significantly increased CRC risks, particularly those with T2DM (HR = 2.28, 95% CI: 1.11, 4.66). As compared to IGF1 19-CA wild-type carriers without T2DM, carrying two IGF1 19-CA variant repeat alleles were associated with a significantly decreased CRC risk in those without T2DM (HR = 0.76, 95% CI: 0.63-0.91). This association was absent when T2DM was present. Our study of joint effects indicated that the presence of unfavorable alleles in the IGF pathway may further increase the risk of CRC associated with T2DM.

Associations of adult-attained height and early life energy restriction with postmenopausal breast cancer risk according to estrogen and progesterone receptor status.

Adult-attained height is a marker for underlying mechanisms, such as cell growth, that may also influence postmenopausal breast cancer (BC) risk, perhaps specifically hormone-sensitive BC subtypes. Early life energy restriction may inhibit these mechanisms, resulting in shorter height and a reduced postmenopausal BC risk. Women (62,573) from the Netherlands Cohort Study completed a self-administered questionnaire in 1986 when 55-69 years old, and were followed-up for 20.3 years (case-cohort: Nsubcohort = 2,438; Ncases = 3,354). Cox multivariable-adjusted hazard ratios (HR) and 95% confidence intervals (CI) were estimated for BC risk overall and by estrogen and progesterone receptor subtypes in relation to height and early life energy restriction during the Hunger Winter, War Years, and Economic Depression. Although energy restriction can only influence longitudinal growth in women exposed before and/or during the growth spurt, it may also influence BC risk when occurring after the growth spurt, possibly through different growth processes. Therefore, Cox analyses were additionally conducted according to timing of energy restriction in relation to the growth spurt. Height was associated with an increased BC risk (HRper 5cm = 1.07, 95%CI:1.01-1.13), particularly hormone receptor-positive BC. Energy restriction before and/or during the growth spurt was associated with a decreased hormone receptor-positive BC risk. Energy restriction during the Hunger Winter increased the estrogen receptor-negative BC risk regardless of the timing of energy restriction. In conclusion, height and energy restriction before and/or during the growth spurt were both associated with hormone receptor-positive BC risk, in the direction as expected, indicating critical exposure windows for hormonal growth-related mechanisms.

Alcohol drinking, ADH1B and ADH1C genotypes and the risk of postmenopausal breast cancer by hormone receptor status: the Netherlands Cohort Study on diet and cancer.

Alcohol consumption has consistently been shown to increase breast cancer (BC) risk. This association may be modified by single nucleotide polymorphisms (SNPs) in alcohol dehydrogenase (ADH) isoenzymes ADH1B and ADH1C. The Netherlands Cohort Study comprises 62 573 women, aged 55-69 years at baseline (1986). Follow-up for postmenopausal BC for 20.3 years was available. Genotyping of six tag SNPs in ADH1B and ADH1C was performed on DNA from toenails. A case-cohort approach was used for analysis (complete data available for nsubcohort = 1301; ncases = 1630). Cox regression models for postmenopausal BC were applied to determine marginal effects of alcohol intake and SNPs using a dominant genetic model, as well as multiplicative interaction of the two. Results were also obtained for subtypes by estrogen receptor (ER) and progesterone receptor (PR) status. Multiple testing was adjusted for by applying the false discovery rate (FDR). Alcohol intake (categorical) increased the risk of postmenopausal BC (Ptrend = 0.031). Trends for ER and PR subgroups followed a similar pattern. Continuous modeling of alcohol resulted in a hazard rate ratio (HR) for overall postmenopausal BC of 1.09 (95% confidence interval: 1.01-1.19) per 10 g/day of alcohol. SNPs were not associated with BC risk. No effect modification of the alcohol-BC association by SNP genotype was seen after FDR correction in overall BC and ER/PR subgroups. In conclusion, alcohol consumption was shown to increase the risk of postmenopausal BC. This association was not significantly modified by common SNPs in ADH1B and ADH1C, neither in overall BC nor in hormone receptor-defined subtypes.

Alcohol intake, ADH1B and ADH1C genotypes, and the risk of colorectal cancer by sex and subsite in the Netherlands Cohort Study.

The alcohol-colorectal cancer (CRC) association may differ by sex and ADH1B and ADH1C genotypes. ADH enzymes oxidize ethanol to acetaldehyde, both of which are human carcinogens. The Netherlands Cohort Study includes 120 852 participants, aged 55-69 years at baseline (1986), and has 20.3 years follow-up (case-cohort: nsubcohort = 4774; ncases = 4597). The baseline questionnaire included questions on alcohol intake at baseline and 5 years before. Using toenail DNA, available for ~75% of the cohort, we successfully genotyped six ADH1B and six ADH1C SNPs (nsubcohort = 3897; ncases = 3558). Sex- and subsite-specific Cox hazard ratios and 95% confidence intervals for CRC were estimated comparing alcohol categories, genotypes within drinkers and alcohol categories within genotype strata. We used a dominant genetic model and adjusted for multiple testing. Alcohol intake increased CRC risk in both sexes, though in women only in the (proximal) colon when in excess of 30 g/day. In male drinkers, ADH1B rs4147536 increased (distal) colon cancer risk. In female drinkers, ADH1C rs283415 increased proximal colon cancer risk. ADH1B rs3811802 and ADH1C rs4147542 decreased CRC risk in heavy (>30 g/day) and stable drinkers (compared to 5 years before baseline), respectively. Rs3811802 and rs4147542 significantly modified the alcohol-colon cancer association in women (Pfor interaction = 0.004 and 0.02, respectively). A difference in associations between genotype strata was generally clearer in men than women. In conclusion, men showed increased CRC risks across subsites and alcohol intake levels, while only colon cancer risk was increased in women at heavy intake levels. ADH1B rs3811802 and ADH1C rs4147542 significantly modified the alcohol-colon cancer association in women.

Energy restriction at young age, genetic variants in the insulin-like growth factor pathway and colorectal cancer risk in the Netherlands Cohort Study.

The energy restriction (ER)-colorectal cancer (CRC) association is inconsistent in literature. To strengthen the biological plausibility of the ER-CRC association, we investigated whether genetic variation in the insulin-like growth factor (IGF) pathway, a putative underlying mechanism, modulated this association in the Netherlands Cohort Study. Participants completed a questionnaire (n = 120,852) and provided toenail clippings for DNA (∼75%) at baseline. Individuals living in a Western city during the Hunger Winter (1944-45) or Western rural versus non-Western area were exposed to (severe) ER at young age. Genotyping was performed for 3,768 subcohort members and 2,580 CRC cases (case-cohort with 16.3 years follow-up). Cox hazard ratios for CRC were estimated across combined categories of ER and a genetic sum score of unfavorable alleles based on 18 single nucleotide polymorphisms in IGF-related genes and ER and an IGF1 19-CA repeat polymorphism. The reference included ER exposed individuals, so that increased hazard ratios were expected in higher combined categories for calculating relative excess risks due to interaction (additive interactions). Wald tests for multiplicative interactions were also performed. Multiplicative and additive interactions were nonsignificant. Combined ER-genetic sum score categories showed increasing CRC risks in men, but confidence intervals were wide. Women carrying two variant IGF1 19-CA repeat alleles versus those carrying two wild type IGF1 19-CA repeat alleles were at an ∼50% decreased CRC risk, irrespective of ER exposure. In conclusion, data indicate that the IGF pathway might be involved in the ER-CRC association in men, but not women, although interactions were nonsignificant, hampering definite conclusions.

Mitochondrial DNA copy number in colorectal cancer: between tissue comparisons, clinicopathological characteristics and survival.

Low mitochondrial DNA (mtDNA) copy number in tumors has been associated with worse prognosis in colorectal cancer (CRC). This study further deciphers the role of mtDNA copy number in CRC by comparing mtDNA copy number between healthy, adenoma and carcinoma tissue, by investigating its association according to several clinicopathological characteristics in CRC, and by relating it to CRC-specific survival in CRC patients. A hospital-based series of samples including cancer, adenoma and adjacent histologically normal tissue from primary CRC patients (n = 56) and recurrent CRC (n = 16) was studied as well as colon mucosa samples from healthy subjects (n = 76). Furthermore, mtDNA copy number was assessed in carcinomas of 693 CRC cases identified from the population-based Netherlands Cohort Study (NLCS). MtDNA copy number was significantly lower in carcinoma tissue (P = 0.011) and adjacent tissue (P < 0.001) compared to earlier resected adenoma tissue and in primary CRC tissue compared to recurrent CRC tissue (P = 0.011). Within both study populations, mtDNA copy number was significantly lower in mutated BRAF (P = 0.027 and P = 0.006) and in microsatellite unstable (MSI) tumors (P = 0.033 and P < 0.001) and higher in KRAS mutated tumors (P = 0.004). Furthermore, the association between mtDNA and survival seemed to follow an inverse U-shape with the highest HR observed in the second quintile of mtDNA copy number (HR = 1.70, 95% CI = 1.18, 2.44) compared to the first quintile. These results might reflect an association of mtDNA copy number with various malignant processes in cancer cells and warrants further research on tumor energy metabolism in CRC prognosis.

Physical activity, occupational sitting time, and colorectal cancer risk in the Netherlands cohort study.

We investigated occupational energy expenditure and sitting time in the longest held job (in men only), nonoccupational physical activity, and former sports participation in relation to colorectal cancer endpoints. The Netherlands Cohort Study includes 120,852 participants who completed a self-administered questionnaire in 1986 when they were aged 55-69 years. By 2002, 1,819 male and 1,366 female colorectal cancer cases were available for case-cohort analyses. In men, higher occupational energy expenditure levels and fewer occupational sitting hours were associated with decreased hazard ratios for colon cancer, particularly distal colon cancer (occupational energy expenditure of ≥12 vs. <8 kJ/minute, hazard ratio (HR) = 0.71, 95% confidence interval (CI): 0.52, 0.97; P for trend = 0.01; occupational sitting hours of <2 vs. 6-8 hours/day, HR = 0.63, 95% CI: 0.48, 0.83; P for trend = 0.001). The median duration of the longest held job for male subcohort members was 29 years. Nonoccupational physical activity was inconsistently associated with colorectal cancer endpoints in men, and it was inversely associated with colon cancer in women, particularly distal colon cancer (>90 vs. ≤30 minutes/day, HR = 0.69, 95% CI: 0.50, 0.96; P for trend = 0.06), and rectal cancer (>90 vs. ≤30 minutes/day, HR = 0.59, 95% CI: 0.39, 0.90; P for trend = 0.02). In conclusion, regular long-term physical activity and fewer sitting hours may protect against colon cancer, particularly distal colon cancer; results for rectal cancer were mixed.

Association between adjuvant therapy and survival in colorectal cancer patients according to metabolic Warburg-subtypes.

PURPOSE: Tumor location and tumor node metastasis (TNM) stage guide treatment decisions in colorectal cancer (CRC) patients. However, patients with the same disease stage do not benefit equally from adjuvant therapy. Hence, there remains an urgent clinical need to identify prognostic and/or predictive biomarker(s) to personalize treatment decisions. In this exploratory study, we investigated whether our previously defined metabolic Warburg-subtypes can predict which CRC patients might derive survival benefit from adjuvant therapy. METHODS: Information regarding treatment (surgery only: n = 1451; adjuvant radiotherapy: n = 82; or adjuvant chemotherapy: n = 260) and Warburg-subtype (Warburg-low: n = 485, -moderate: n = 641, or -high: n = 667) was available for 1793 CRC patients from the Netherlands Cohort Study (NLCS). Kaplan-Meier curves and Cox regression models were used to investigate survival benefit from adjuvant therapy compared to surgery-only for the different Warburg-subtypes. RESULTS: Patients with Warburg-moderate CRC (HRCRC-specific 0.64; 95% CI 0.47-0.86, HRoverall 0.61; 95% CI 0.47-0.80), and possibly Warburg-high CRC (HRCRC-specific 0.86; 95% CI 0.65-1.14, HRoverall 0.82; 95% CI 0.64-1.05), had survival benefit from adjuvant therapy. No survival benefit was observed for patients with Warburg-low CRC (HRCRC-specific 1.07; 95% CI 0.76-1.52, HRoverall 0.95; 95% CI 0.70-1.30). There was a significant interaction between Warburg-subtype and adjuvant therapy for CRC-specific survival (p = 0.049) and overall survival (p = 0.035). CONCLUSION: Our results suggest that Warburg-subtypes may predict survival benefit from adjuvant therapy in CRC patients. A survival benefit from adjuvant therapy was observed for patients with Warburg-moderate and possibly Warburg-high CRC, but not for patients with Warburg-low CRC. Future prospective studies are necessary to validate our findings.

Association between mutational subgroups, Warburg-subtypes, and survival in patients with colorectal cancer.

BACKGROUND: Previous research suggests that Warburg-subtypes are related to potentially important survival differences in colorectal cancer (CRC) patients. In the present study, we investigated whether mutational subgroups based on somatic mutations in RAS, BRAF, PIK3CA, and MET, which are known to promote the Warburg-effect, as well as mismatch repair (MMR) status, hold prognostic value in CRC. In addition, we investigated whether Warburg-subtypes provide additional prognostic information, independent of known prognostic factors like TNM stage. METHODS: CRC patients (n = 2344) from the prospective Netherlands Cohort Study (NLCS) were classified into eight mutually exclusive mutational subgroups, based on observed mutations in RAS, BRAF, PIK3CA, and MET, and MMR status: All-wild-type + MMRproficient , KRASmut  + MMRproficient , KRASmut  + PIK3CAmut  + MMRproficient , PIK3CAmut  + MMRproficient , BRAFmut  + MMRproficient , BRAFmut  + MMRdeficient , other + MMRproficient , and other + MMRdeficient . Kaplan-Meier curves and Cox regression models were used to investigate associations between mutational subgroups and survival, as well as associations between our previously established Warburg-subtypes and survival within these mutational subgroups. RESULTS: Compared to patients with all-wild-type + MMRproficient CRC, patients with KRASmut  + MMRproficient , KRASmut  + PIK3CAmut  + MMRproficient , BRAFmut  + MMRproficient , or other + MMRproficient CRC had a statistically significant worse survival (HRCRC-specific ranged from 1.29 to 1.88). In contrast, patients with other + MMRdeficient CRC had the most favorable survival (HRCRC-specific 0.48). No statistically significant survival differences were observed for the Warburg-subtypes within mutational subgroups. CONCLUSION: Our results highlight the prognostic potential of mutational subgroups in CRC. Warburg-subtypes did not provide additional prognostic information within these mutational subgroups. Future larger-scale prospective studies are necessary to validate our findings and to examine the potential clinical utility of CRC subtyping based on mutational subgroups.

Energy Balance-Related Factors and Risk of Colorectal Cancer Expressing Different Levels of Proteins Involved in the Warburg Effect.

BACKGROUND: Energy balance-related factors [body mass index (BMI), waist circumference, physical activity] have been associated with colorectal cancer risk. Warburg effect activation via PI3K/Akt signaling is one of the proposed mechanisms. We investigated whether energy balance-related factors were associated with risk of Warburg subtypes in colorectal cancer. METHODS: We investigated this using immunohistochemistry for six proteins involved in the Warburg effect (LDHA, GLUT1, MCT4, PKM2, P53, PTEN) on tissue microarrays of 2,399 incident colorectal cancer cases from the prospective Netherlands Cohort Study (ntotal = 120,852; nsubcohort = 5,000; aged 55-69 in 1986; 20.3 years follow-up). Data analyses included 3,911 subcohort members and 1,972 colorectal cancer cases with complete covariate data. Expression levels of all proteins were combined into a pathway-based sum score and categorized into three "Warburg subtypes" (Warburg-low/moderate/high). Multivariable Cox regression analyses were used to estimate associations of BMI, clothing size (waist circumference proxy), and physical activity with Warburg subtypes in colorectal cancer. RESULTS: BMI and clothing size were positively associated with Warburg-moderate and Warburg-high colon cancer risk in men (Pheterogeneity = 0.192). In women, clothing size was positively associated with Warburg-low and Warburg-high colon cancer (Pheterogeneity = 0.005). Nonoccupational physical activity was inversely associated with Warburg-low and Warburg-moderate colon cancer in women (Pheterogeneity = 0.045), but positively associated with Warburg-high rectal cancer in men (Pheterogeneity = 0.089). CONCLUSIONS: The Warburg effect might be involved in associations between adiposity and colon cancer risk, though additional mechanisms could be at play in women as well. The inverse association between physical activity and colon cancer might be explained by mechanisms other than the Warburg effect. IMPACT: Further research is needed to reproduce these results and investigate possible additional mechanisms.

Polymorphisms in the mTOR-PI3K-Akt pathway, energy balance-related exposures and colorectal cancer risk in the Netherlands Cohort Study.

BACKGROUND: The mTOR-PI3K-Akt pathway influences cell metabolism and (malignant) cell growth. We generated sex-specific polygenic risk scores capturing natural variation in 7 out of 10 top-ranked genes in this pathway. We studied the scores directly and in interaction with energy balance-related factors (body mass index (BMI), trouser/skirt size, height, physical activity, and early life energy restriction) in relation to colorectal cancer (CRC) risk in the Netherlands Cohort Study (NLCS) (n=120,852). The NLCS has a case-cohort design and 20.3 years of follow-up. Participants completed a baseline questionnaire on diet and cancer in 1986 when 55-69 years old. ~75% of the cohort returned toenail clippings used for DNA isolation and genotyping (n subcohort=3,793, n cases=3,464). To generate the scores, the dataset was split in two and risk alleles were defined and weighted based on sex-specific associations with CRC risk in the other dataset half, because there were no SNPs in the top-ranked genes associated with CRC risk in previous genome-wide association studies at a significance level p<1*10-5. RESULTS: Cox regression analyses showed positive associations between the sex-specific polygenic risk scores and colon but not rectal cancer risk in men and women, with hazard ratios for continuously modeled scores close to 1.10. There was no modifying effect observed of the scores on associations between the energy balance-related factors and CRC risk. However, BMI (in men), non-occupational physical activity (in women), and height (in men and women) were associated with the risk of CRC, in particular (proximal and distal) colon cancer, in the direction as expected in the lower tertiles of the sex-specific polygenic risk scores. CONCLUSIONS: Current data suggest that the mTOR-PI3K-Akt pathway may be involved in colon cancer development. This study thereby sheds more light on colon cancer etiology through use of genetic variation in the mTOR-PI3K-Akt pathway.

Energy balance-related factors and risk of colorectal cancer based on KRAS, PIK3CA, and BRAF mutations and MMR status.

INTRODUCTION: KRAS mutations (KRASmut), PIK3CAmut, BRAFmut, and mismatch repair deficiency (dMMR) have been associated with the Warburg-effect. We previously observed differential associations between energy balance-related factors (BMI, clothing-size, physical activity) and colorectal cancer (CRC) subtypes based on the Warburg-effect. We now investigated whether associations between energy balance-related factors and risk of CRC differ between subgroups based on mutation and MMR status. METHODS: Information on molecular features was available for 2349 incident CRC cases within the Netherlands Cohort Study (NLCS), with complete covariate data available for 1934 cases and 3911 subcohort members. Multivariable-adjusted Cox-regression was used to estimate associations of energy balance-related factors with risk of CRC based on individual molecular features (KRASmut; PIK3CAmut; BRAFmut; dMMR) and combinations thereof (all-wild-type + MMR-proficient (pMMR); any-mutation/dMMR). RESULTS: In men, BMI and clothing-size were positively associated with risk of colon, but not rectal cancer, regardless of molecular features subgroups; the strongest associations were observed for PIK3CAmut colon cancer. In women, however, BMI and clothing-size were only associated with risk of KRASmut colon cancer (p-heterogeneityKRASmut versus all-wild-type+pMMR = 0.008). Inverse associations of non-occupational physical activity with risk of colon cancer were strongest for any-mutation/dMMR tumors in men and women, and specifically for PIK3CAmut tumors in women. Occupational physical activity was inversely associated with both combination subgroups of colon cancer in men. CONCLUSION: In men, associations did not vary according to molecular features. In women, a role of KRAS mutations in the etiological pathway between adiposity and colon cancer is suggested, and of PIK3CA mutations between physical activity and colon cancer.

Body size and colorectal cancer risk after 16.3 years of follow-up: an analysis from the Netherlands Cohort Study.

A large body size may differentially influence risk of colorectal cancer (CRC) by anatomic location. The Netherlands Cohort Study includes 120,852 men and women aged 55-69 years who self-reported weight, height, and trouser/skirt size at baseline (1986), as well as weight at age 20 years. Derived variables included body mass index (BMI; weight (kg)/height (m)(2)), BMI at age 20 years, and BMI change. After 16.3 years of follow-up (1986-2002), 2,316 CRC cases were available for case-cohort analysis. In men, the highest risk estimates were observed for body fat (per 5-unit increase in BMI, hazard ratio (HR) = 1.25, 95% confidence interval (CI): 1.05, 1.46; for highest quintile of trouser size vs. lowest, HR = 1.63, 95% CI: 1.17, 2.29 (P-trend = 0.02)) and appeared more closely associated with distal colon tumors (for BMI (5-unit increase), HR = 1.42, 95% CI: 1.13, 1.79; for highest quintile of trouser size, HR = 2.56, 95% CI: 1.55, 4.24 (P-trend < 0.01)) than with proximal colon or rectal tumors. In women, body fat was not associated with CRC risk unless it was considered simultaneously with physical activity; a large trouser/skirt size and a low level of physical activity increased risk for all subtypes. Height was associated with risk of CRC, especially distal colon tumors (highest quintile vs. lowest: HR = 1.53, 95% CI: 1.03, 2.27; P-trend = 0.05), in women only.

Validity and Reproducibility of Immunohistochemical Scoring by Trained Non-Pathologists on Tissue Microarrays.

BACKGROUND: Scoring of immunohistochemistry (IHC) staining is often done by non-pathologists, especially in large-scale tissue microarray (TMA)-based studies. Studies on the validity and reproducibility of scoring results from non-pathologists are limited. Therefore, our main aim was to assess interobserver agreement between trained non-pathologists and an experienced histopathologist for three IHC markers with different subcellular localization (nucleus/membrane/cytoplasm). METHODS: Three non-pathologists were trained in recognizing adenocarcinoma and IHC scoring by a senior histopathologist. Kappa statistics were used to analyze interobserver and intraobserver agreement for 6,249 TMA cores from a colorectal cancer series. RESULTS: Interobserver agreement between non-pathologists (independently scored) and the histopathologist was "substantial" for nuclear and membranous IHC markers (κrange = 0.67-0.75 and κrange = 0.61-0.69, respectively), and "moderate" for the cytoplasmic IHC marker (κrange = 0.43-0.57). Scores of the three non-pathologists were also combined into a "combination score" (if at least two non-pathologists independently assigned the same score to a core, this was the combination score). This increased agreement with the pathologist (κnuclear = 0.74; κmembranous = 0.73; κcytopasmic = 0.57). Interobserver agreement between non-pathologists was "substantial" (κnuclear = 0.78; κmembranous = 0.72; κcytopasmic = 0.61). Intraobserver agreement of non-pathologists was "substantial" to "almost perfect" (κnuclear,range = 0.83-0.87; κmembranous,range = 0.75-0.82; κcytopasmic = 0.69). Overall, agreement was lowest for the cytoplasmic IHC marker. CONCLUSIONS: This study shows that adequately trained non-pathologists are able to generate reproducible IHC scoring results, that are similar to those of an experienced histopathologist. A combination score of at least two non-pathologists yielded optimal results. IMPACT: Non-pathologists can generate reproducible IHC results after appropriate training, making analyses of large-scale molecular pathological epidemiology studies feasible within an acceptable time frame.

Bowel movement and constipation frequencies and the risk of colorectal cancer among men in the Netherlands Cohort Study on Diet and Cancer.

The authors investigated the associations between bowel movement and constipation frequencies and colorectal cancer (CRC) endpoints among men in the Netherlands Cohort Study on Diet and Cancer (n = 58,279) and explored whether dietary fiber intake may modify associations. After 13.3 years (1986-1999), 1,207 CRC cases and 1,753 subcohort members were available for case-cohort analyses. Multivariate analyses showed a significantly increased hazard ratio for CRC overall and rectal cancer in men who reported having a bowel movement 1-2 times per day (second-highest category) as compared with once a day (CRC: hazard ratio (HR) = 1.29, 95% confidence interval (CI): 1.09, 1.53 (P(trend) < 0.001); rectal cancer: HR = 1.50, 95% CI: 1.15, 1.95 (P(trend) = 0.001)). Hazard ratios for CRC overall and rectal cancer were significantly decreased and lowest in men who reported suffering from constipation sometimes or more often versus never (CRC: HR = 0.76, 95% CI: 0.58, 0.98 (P(trend) = 0.02); rectal cancer: HR = 0.57, 95% CI: 0.35, 0.90 (P(trend) = 0.01)). No trends in the associations with proximal or distal colon cancer risk were observed. Interactions with dietary fiber intake were not significant. In this study, frequent bowel movements were associated with an increased risk of rectal cancer in men, and constipation was associated with a decreased risk.

Fluid intake and colorectal cancer risk in the Netherlands Cohort Study.

Total fluid intake, specifically water intake, has been suggested to protect against colorectal cancer. We examined the association of total fluid intake with colorectal cancer endpoints and possible effect modification by fiber intake within the Netherlands Cohort Study (N = 120,852). We also investigated intake of specific beverages. After 13.3 yr, 1,443 male and 1,040 female colorectal cancer cases with complete baseline questionnaires were available for case-cohort analyses. Multivariate analyses showed no dose-response relationship of total fluid intake and intake of specific beverages with the risk of overall colorectal, proximal, and distal colon cancer. For rectal cancer risk in men, there was a nonsignificant positive trend for total fluid intake [> 1,500 vs. 6 vs.