Large differences in global transcriptional regulatory programs of normal and tumor colon cells.

BACKGROUND: Dysregulation of transcriptional programs leads to cell malfunctioning and can have an impact in cancer development. Our study aims to characterize global differences between transcriptional regulatory programs of normal and tumor cells of the colon. METHODS: Affymetrix Human Genome U219 expression arrays were used to assess gene expression in 100 samples of colon tumor and their paired adjacent normal mucosa. Transcriptional networks were reconstructed using ARACNe algorithm using 1,000 bootstrap replicates consolidated into a consensus network. Networks were compared regarding topology parameters and identified well-connected clusters. Functional enrichment was performed with SIGORA method. ENCODE ChIP-Seq data curated in the hmChIP database was used for in silico validation of the most prominent transcription factors. RESULTS: The normal network contained 1,177 transcription factors, 5,466 target genes and 61,226 transcriptional interactions. A large loss of transcriptional interactions in the tumor network was observed (11,585; 81% reduction), which also contained fewer transcription factors (621; 47% reduction) and target genes (2,190; 60% reduction) than the normal network. Gene silencing was not a main determinant of this loss of regulatory activity, since the average gene expression was essentially conserved. Also, 91 transcription factors increased their connectivity in the tumor network. These genes revealed a tumor-specific emergent transcriptional regulatory program with significant functional enrichment related to colorectal cancer pathway. In addition, the analysis of clusters again identified subnetworks in the tumors enriched for cancer related pathways (immune response, Wnt signaling, DNA replication, cell adherence, apoptosis, DNA repair, among others). Also multiple metabolism pathways show differential clustering between the tumor and normal network. CONCLUSIONS: These findings will allow a better understanding of the transcriptional regulatory programs altered in colon cancer and could be an invaluable methodology to identify potential hubs with a relevant role in the field of cancer diagnosis, prognosis and therapy.

Screening and prostate-cancer mortality in a randomized European study.

BACKGROUND: The European Randomized Study of Screening for Prostate Cancer was initiated in the early 1990s to evaluate the effect of screening with prostate-specific-antigen (PSA) testing on death rates from prostate cancer. METHODS: We identified 182,000 men between the ages of 50 and 74 years through registries in seven European countries for inclusion in our study. The men were randomly assigned to a group that was offered PSA screening at an average of once every 4 years or to a control group that did not receive such screening. The predefined core age group for this study included 162,243 men between the ages of 55 and 69 years. The primary outcome was the rate of death from prostate cancer. Mortality follow-up was identical for the two study groups and ended on December 31, 2006. RESULTS: In the screening group, 82% of men accepted at least one offer of screening. During a median follow-up of 9 years, the cumulative incidence of prostate cancer was 8.2% in the screening group and 4.8% in the control group. The rate ratio for death from prostate cancer in the screening group, as compared with the control group, was 0.80 (95% confidence interval [CI], 0.65 to 0.98; adjusted P=0.04). The absolute risk difference was 0.71 death per 1000 men. This means that 1410 men would need to be screened and 48 additional cases of prostate cancer would need to be treated to prevent one death from prostate cancer. The analysis of men who were actually screened during the first round (excluding subjects with noncompliance) provided a rate ratio for death from prostate cancer of 0.73 (95% CI, 0.56 to 0.90). CONCLUSIONS: PSA-based screening reduced the rate of death from prostate cancer by 20% but was associated with a high risk of overdiagnosis. (Current Controlled Trials number, ISRCTN49127736.)

Immune translational control by CPEB4 regulates intestinal inflammation resolution and colorectal cancer development.

Upon tissue injury, cytokine expression reprogramming transiently remodels the inflammatory immune microenvironment to activate repair processes and subsequently return to homeostasis. However, chronic inflammation induces permanent changes in cytokine production which exacerbate tissue damage and may even favor tumor development. Here, we address the contribution of post-transcriptional regulation, by the RNA-binding protein CPEB4, to intestinal immune homeostasis and its role in inflammatory bowel diseases (IBD) and colorectal cancer (CRC) development. We found that intestinal damage induces CPEB4 expression in adaptive and innate immune cells, which is required for the translation of cytokine mRNA(s) such as the one encoding interleukin-22. Accordingly, CPEB4 is required for the development of gut-associated lymphoid tissues and to maintain intestinal immune homeostasis, mediating repair and remodeling after acute inflammatory tissue damage and promoting the resolution of intestinal inflammation. CPEB4 is chronically overexpressed in inflammatory cells in patients with IBD and in CRC, favoring tumor development.

Erratum: The metabolic co-regulator PGC1α suppresses prostate cancer metastasis.

This corrects the article DOI: 10.1038/ncb3357.

Polymorphisms in metabolic genes related to tobacco smoke and the risk of gastric cancer in the European prospective investigation into cancer and nutrition.

Metabolizing enzymes, which often display genetic polymorphisms, are involved in the activation of compounds present in tobacco smoke that may be relevant to gastric carcinogenesis. We report the results of a study looking at the association between risk of gastric adenocarcinoma and polymorphisms in genes CYP1A1, CYP1A2, EPHX1, and GSTT1. A nested case-control study was carried out within the European Prospective Investigation into Cancer and Nutrition, developed in 10 European countries. The study includes 243 newly diagnosed cases of histologically confirmed gastric adenocarcinoma and 946 controls matched by center, age, sex, and date of blood collection. Genotypes were determined in nuclear DNA from WBCs. We found an increased risk of gastric cancer for homozygotes for C (histidine) variant in Y113H of EPHX1 (odds ratio, 1.91; 95% confidence interval, 1.19-3.07) compared with subjects with TC/TT. There was also a significant increased risk for smokers carrying at least one variant allele A in Ex7+129C>A (m4) of CYP1A1 and never smokers with null GSTT1 and allele A in the locus -3859G>A of CYP1A2. Most of these genes are involved in the activation and detoxification of polycyclic aromatic hydrocarbons, suggesting a potential role of these compounds in gastric carcinogenesis.

The metabolic co-regulator PGC1α suppresses prostate cancer metastasis.

Cellular transformation and cancer progression is accompanied by changes in the metabolic landscape. Master co-regulators of metabolism orchestrate the modulation of multiple metabolic pathways through transcriptional programs, and hence constitute a probabilistically parsimonious mechanism for general metabolic rewiring. Here we show that the transcriptional co-activator peroxisome proliferator-activated receptor gamma co-activator 1α (PGC1α) suppresses prostate cancer progression and metastasis. A metabolic co-regulator data mining analysis unveiled that PGC1α is downregulated in prostate cancer and associated with disease progression. Using genetically engineered mouse models and xenografts, we demonstrated that PGC1α opposes prostate cancer progression and metastasis. Mechanistically, the use of integrative metabolomics and transcriptomics revealed that PGC1α activates an oestrogen-related receptor alpha (ERRα)-dependent transcriptional program to elicit a catabolic state and metastasis suppression. Importantly, a signature based on the PGC1α-ERRα pathway exhibited prognostic potential in prostate cancer, thus uncovering the relevance of monitoring and manipulating this pathway for prostate cancer stratification and treatment.

Dietary intake of polycyclic aromatic hydrocarbons in a Spanish population.

The objective of the present study was to estimate the dietary intake of polycyclic aromatic hydrocarbons (PAHs), particularly benzo[a]pyrene (B[a]P), as well as to identify the principal dietary sources of such compounds in the Spanish adult population. The study included 40,690 subjects aged 35 to 64 years from five regions of Spain that were included in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Spain cohort. Usual food intake was estimated by personal interview through a computerized version of a dietary history questionnaire. The estimations of B[a]P and total PAHs were made, taking into account the country where the determinations of content of these compounds in the foods came from and the year of publication. The mean intake of B[a]P in the population was 0.14 microg/day, and the mean intake of total PAHs was 8.57 microg/day. Both for B[a]P and total PAHs, women had a significantly lower mean intake than men, and older people consumed lesser amounts than younger people. Furthermore, the intake was higher in the northern regions. There were no significant differences by smoking status. The food groups of meat and meat products, cereals, and oils and fats contribute 55.5% to the total B[a]P intake, while cereals and meat and meat products contribute 61% to the total PAH consumption. Our estimations of B[a]P intake were lower than in the United Kingdom and The Netherlands, were similar to those found in other studies from Spain and Italy, and were higher than those in the United States and Norway.

Changes in smoking habits in adults: results from a prospective study in Spain.

PURPOSE: We assessed changes in smoking behavior and its related factors among healthy adults from five regions in Spain. METHODS: The smoking status at recruitment and after 3 years was compared in 14,288 men and 23,983 women aged 35 to 64 years. The pattern of smoking and several lifestyle factors were investigated as potential predictors of subsequent changes in smoking habits. RESULTS: Among current smokers at baseline the age-adjusted rates of cessation per 1000 person-years were 57.4 for men and 43.2 for women. Among former smokers at baseline the relapse rates were 37.6 and 48.8 per 1000 person-years for men and women, respectively. The initiation rate per 1000 person-years among men who had never smoked was 12.5 and 2.7 for women. Higher amount currently smoked and longer time since quitting were strong predictors of lower rates of cessation and relapse, respectively, while age was associated with lower initiation rates in women. Increased alcohol consumption was related to low cessation and high relapse and initiation rates, mainly among men, while more educated women had higher cessation and initiation rates. CONCLUSIONS: The current pattern of changes in smoking behavior in Spanish populations aged 35 to 64 years results in rather small prevalence reduction. Additional efforts should be made to promote successful cessation and prevent initiation to reduce the tobacco burden in Spain.

[The European prospective investigation about cancer and nutrition (EPIC)]. / El Estudio Prospectivo Europeo Sobre Cáncer y Nutrición (EPIC).

EPIC is a prospective multi-center study coordinated by the International Agency for Research on Cancer (IARC) operating under the WHO which commenced in 1993 with the collecting of data and blood samples at twenty-three centers in ten European countries (Germany, Denmark, Spain, France, Greece, the Netherlands, Italy, Norway, the United Kingdom and Sweden). In Spain, this study was conducted in five geographic areas (Asturias, Granada, Guipuzcoa, Murcia and Navarre). This study included a total of 519,978 individuals (366,521 of whom were females), blood samples for laboratory analysis being available for a total of 385,719 of these individuals. To date, a total of 24,195 incident cancer cases have been identified. The results of the food intake comparison among the twenty-three European centers were published in 2002, in a European Nutrition journal supplement. The initial EPIC results concerning the relationship between diet and cancer show the intake of fiber, fruits and vegetables to have an effect on protect against colon and rectal cancer, the intake of fruits to have an effect on protect against lung cancer and the intake of fruits and vegetables on the upper digestive tract, whilst a high intake of fruits and vegetables has been shown to have no effect on prostate cancer. Using a seven-day diary for evaluating saturated fat intake, a high intake of saturated fats has been shown to increase the risk of breast cancer.

Gene expression differences between colon and rectum tumors.

PURPOSE: Colorectal cancer studies typically include both colon and rectum tumors as a common entity, though this assumption is controversial and only minor differences have been reported at the molecular and epidemiologic level. We conducted a molecular study based on gene expression data of tumors from colon and rectum to assess the degree of similarity between these cancer sites at transcriptomic level. EXPERIMENTAL DESIGN: A pooled analysis of 460 colon tumors and 100 rectum tumors from four data sets belonging to three independent studies was conducted. Microsatellite instable tumors were excluded as these are known to have a different expression profile and have a preferential proximal colon location. Expression differences were assessed with linear models, and significant genes were identified using adjustment for multiple comparisons. RESULTS: Minor differences at a gene expression level were found between tumors arising in the proximal colon, distal colon, or rectum. Only several HOX genes were found to be associated with tumor location. More differences were found between proximal and distal colon than between distal colon and rectum. CONCLUSIONS: Microsatellite stable colorectal cancers do not show major transcriptomic differences for tumors arising in the colon or rectum. The small but consistent differences observed are largely driven by the HOX genes. These results may have important implications in the design and interpretation of studies in colorectal cancer.

Prostate cancer mortality reduction by prostate-specific antigen-based screening adjusted for nonattendance and contamination in the European Randomised Study of Screening for Prostate Cancer (ERSPC).

BACKGROUND: Prostate-specific antigen (PSA) based screening for prostate cancer (PCa) has been shown to reduce prostate specific mortality by 20% in an intention to screen (ITS) analysis in a randomised trial (European Randomised Study of Screening for Prostate Cancer [ERSPC]). This effect may be diluted by nonattendance in men randomised to the screening arm and contamination in men randomised to the control arm. OBJECTIVE: To assess the magnitude of the PCa-specific mortality reduction after adjustment for nonattendance and contamination. DESIGN, SETTING, AND PARTICIPANTS: We analysed the occurrence of PCa deaths during an average follow-up of 9 yr in 162,243 men 55-69 yr of age randomised in seven participating centres of the ERSPC. Centres were also grouped according to the type of randomisation (ie, before or after informed written consent). INTERVENTION: Nonattendance was defined as nonattending the initial screening round in ERSPC. The estimate of contamination was based on PSA use in controls in ERSPC Rotterdam. MEASUREMENTS: Relative risks (RRs) with 95% confidence intervals (CIs) were compared between an ITS analysis and analyses adjusting for nonattendance and contamination using a statistical method developed for this purpose. RESULTS AND LIMITATIONS: In the ITS analysis, the RR of PCa death in men allocated to the intervention arm relative to the control arm was 0.80 (95% CI, 0.68-0.96). Adjustment for nonattendance resulted in a RR of 0.73 (95% CI, 0.58-0.93), and additional adjustment for contamination using two different estimates led to estimated reductions of 0.69 (95% CI, 0.51-0.92) to 0.71 (95% CI, 0.55-0.93), respectively. Contamination data were obtained through extrapolation of single-centre data. No heterogeneity was found between the groups of centres. CONCLUSIONS: PSA screening reduces the risk of dying of PCa by up to 31% in men actually screened. This benefit should be weighed against a degree of overdiagnosis and overtreatment inherent in PCa screening.

Dietary patterns and survival of older Europeans: the EPIC-Elderly Study (European Prospective Investigation into Cancer and Nutrition).

OBJECTIVE: To investigate the association of a posteriori dietary patterns with overall survival of older Europeans. DESIGN AND SETTING: This is a multi-centre cohort study. Cox regression analysis was used to investigate the association of the prevailing, a posteriori-derived, plant-based dietary pattern with all-cause mortality in a population of subjects who were 60 years or older at recruitment to the European Prospective Investigation into Cancer and Nutrition (EPIC-Elderly cohort). Analyses controlled for all known potential risk factors. SUBJECTS: In total, 74,607 men and women, 60 years or older at enrolment and without previous coronary heart disease, stroke or cancer, with complete information about dietary intakes and potentially confounding variables, and with known survival status as of December 2003, were included in the analysis. RESULTS: An increase in the score which measures the adherence to the plant-based diet was associated with a lower overall mortality, a one standard deviation increment corresponding to a statistically significant reduction of 14% (95% confidence interval 5-23%). In country-specific analyses the apparent association was stronger in Greece, Spain, Denmark and The Netherlands, and absent in the UK and Germany. CONCLUSIONS: Greater adherence to the plant-based diet that was defined a posteriori in this population of European elders is associated with lower all-cause mortality. This dietary score is moderately positively correlated with the Modified Mediterranean Diet Score that has been constructed a priori and was also shown to be beneficial for the survival of the same EPIC-Elderly cohort.

Extent of prostate-specific antigen contamination in the Spanish section of the European Randomized Study of Screening for Prostate Cancer (ERSPC).

OBJECTIVES: The performance of tests outside prostate cancer screening trials (PSA contamination) may affect their statistical power. The present study addressed the extent of PSA contamination in the Spanish section of the European Randomized Study of Screening for Prostate Cancer (ERSPC) and its impact on biopsy performance and prostate cancer detection. METHODS: Data linkage was performed to address screening-related interventions outside the study. Four databases were used: (1) Spanish ERSPC database (n=4278), (2) laboratory database with all PSA determinations (n=31,140), (3) database of 1608 prostate biopsies, and (4) records of all prostate cancers (n=819) diagnosed at our centre. PSA contamination, biopsy performance, and cancer detection rates were calculated. RESULTS: Median follow-up time was 6.6 yr. A total of 2201 PSA determinations were performed for 1253 men. Cumulative PSA contamination was 29.3% (17% in the control arm during the first 4 yr). A higher proportion of men undergoing biopsies was found in the screening arm (21.3% vs. 2.9% in the control arm, p<0.0001). Similarly, higher cancer detection rates were found in the screening (4.7% vs. 1.2% in the control arm, p<0.0001). CONCLUSIONS: In our experience, the PSA contamination rate has increased during the last years, but its impact on biopsy performance and cancer detection in the control arm of the trial is limited and not likely to compromise the statistical power of the ERSPC trial.

Intake and food sources of nitrites and N-nitrosodimethylamine in Spain.

OBJECTIVE: To conduct a comprehensive assessment of dietary intakes of nitrites and N-nitrosodimethylamine (NDMA). SUBJECTS AND SETTING: A study was conducted within the Spanish cohort of the European Prospective Investigation in Cancer and Nutrition (EPIC) to assess the intake and food sources of these compounds in Spanish adults. The study included 41,446 health volunteers, aged 29-69 years, from Northern and Southern regions. Usual food intake was estimated by in-person interviews using a computerised dietary questionnaire. RESULTS: The estimated geometric mean was 0.994 mg day(-1) for nitrites and 0.114 microg day(-1) for NDMA. For both compounds a positive trend in consumption with increasing energy intake was observed. Dietary NDMA was related to age and sex after energy adjustment, while nitrite consumption increased with higher intakes of vitamin C (P < 0.001). The food groups that contributed most to intakes were meat products, cereals, vegetables and fruits for nitrites, and processed meat, beer, cheese and broiled fish for NDMA. Current and past smokers, who had high levels of NDMA from tobacco exposure, were also identified as the highest consumers of dietary NDMA. Furthermore, smokers had low intakes of vitamin C (an inhibitor of endogenous nitrosation). CONCLUSIONS: Intake levels of NDMA and nitrites in a Mediterranean cohort are currently relatively lower than those previously reported, although processed meat, beer and cured cheese still are the most important contributors to NDMA intake.

Adherence to a Mediterranean diet is associated with reduced 3-year incidence of obesity.

Few studies have prospectively examined dietary patterns and adult weight change, and results to date are inconsistent. This study examines whether a Mediterranean diet (MD) pattern is associated with reduced 3-y incidence of obesity using data from the Spanish cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC-Spain). The sample included 17,238 women and 10,589 men not obese and aged 29-65 y at baseline (1992-96). Height and weight were measured at baseline; weight was self-reported in a follow-up survey a mean of 3.3 y later. Detailed dietary history data, collected using a validated method, were used to construct a MD score. Logistic regression models were used to estimate odds of becoming overweight or obese. Among initially overweight subjects, 7.9% of women and 6.9% of men became obese, whereas 13.8% of normal weight men and 23.0% women became overweight. High MD adherence was associated with significantly lower likelihood of becoming obese among overweight subjects, with stronger associations after adjusting for underreporting of dietary data. Associations (odds ratios with 95% CI) were similar in women (0.69, 0.54-0.89) and men (0.68, 0.53-0.89). Adjusting for the plausibility of reported dietary intakes increased the magnitude of these associations, which were approximately 0.8 without this adjustment. MD adherence was not associated with incidence of overweight in initially normal-weight subjects. Nonetheless, results suggest that promoting eating habits consistent with MD patterns may be a useful part of efforts to combat obesity.

Prostate cancer detection is also relevant in low prostate specific antigen ranges.

OBJECTIVE: To address detection rates and clinical features of the cancers detected with low prostate specific antigen (PSA) levels. METHODS: In the context of a prostate cancer (PCa) screening program 1097 men attended to a new rescreen round. Sextant prostate biopsy was recommended when PSA > or =3 ng/ml. We also recommended to undergo biopsy in the range 1.0-2.99 ng/ml when free to total (f/t) PSA ratio < or =20%. Detection rate was calculated and clinical features of the cancers detected were studied. RESULTS: Mean age was 61.1 years. A total of 497 (45.3%) had total PSA <1.0 ng/ml, 439 (40%) between 1.0 and 2.99 ng/ml, and 161 (14.7%) > or =3.0 ng/ml. In the group with PSA between 1.0 and 2.99 ng/ml and f/t PSA ratio < or =20% a total of 249 biopsies were indicated (159 performed, acceptance 63.9%), and 15 cancers detected (detection rate 9.4%). Biopsy was recommended to 72 men with PSA between 3.0 and 3.99 ng/ml, performed in 56 (77.8%), and 12 tumors detected (detection rate 21.4%). All cancers in the study were clinically localized. Only 4 out of 15 cancers with PSA in the range 1.0-2.99 ng/ml (26.7%) fulfilled clinical criteria of insignificant cancer. Two were poorly differentiated and found to have patologically extracapsular disease. None of the 12 patients with PCa and PSA between 3.0 and 3.99 ng/ml had poorly differentiated features and only one complied with criteria of insignificant cancer. One out of seven who underwent RRP was found to have extracapsular disease. CONCLUSIONS: Cancer detection in low PSA ranges is lower but still relevant. The detection of potentially aggresive cancers is still of concern.

PSA-use in a Spanish industrial area.

OBJECTIVES: To document the extent of prostate-specific antigen (PSA)-testing in the general population at Getafe (Spain) outside our prostate cancer (PC) screening program, and to check its performance in terms of PC detection. METHODS: A total of 5371 PSA-test records (1997-1999) were reviewed and testing rates estimated per 1000 person-years. The extent of patient referral (men referred to our facilities) was calculated adjusting for PSA levels. To approach the performance of testing in the general population, our PC screening program acted as a standard for comparison. The probability of missing one PC in the general population was estimated in terms of number of men necessary to screen (NNS). Calculations were made adjusting for PSA levels. RESULTS: PSA-testing rate in the general population was 21.6/1000 person-years. In the age-group 55-69 years, this rate was 86.8/1000 (152.6 in men >70 years). Referral rates were 67.9 and 39.5% for men with PSA 4-10 and >10 ng/ml, respectively. Overall PC detection rate was 1.76%. Detection rates for PSA 4-10 and >10 ng/ml were 4.66 and 12.94%, respectively. When compared with the performance of the screening program, for every 17 men with a PSA in the range 4-10 ng/ml one cancer was missed (95% confidence interval (CI), 9-580). Similarly, one cancer was lost for every four men with a PSA >10 ng/ml (95% CI, 2-8). CONCLUSIONS: The extent of opportunistic testing in our setting is very high, particularly in the older age groups. Opportunistic screening renders PC detection rates lower than expected for every PSA level and cannot be encouraged.

Dietary sources of vitamin C, vitamin E and specific carotenoids in Spain.

A cross-sectional study was conducted within the Spanish cohort of the European Prospective Investigation in Cancer and Nutrition to assess the principal food sources of vitamin C, vitamin E, alpha-carotene, beta-carotene, lycopene, lutein, beta-cryptoxanthin and zeaxanthin in an adult Spanish population. The study included 41446 healthy volunteers (25812 women and 15634 men), aged 29-69 years, from three Spanish regions in the north (Asturias, Navarra and Guipúzcoa) and two in the south (Murcia and Granada). Usual food intake was estimated by personal interview through a computerized version of a dietary history questionnaire. Foods that provided at least two-thirds of the studied nutrients were: fruits (mainly oranges) (51 %) and fruiting vegetables (mainly tomato and sweet pepper) (20 %) for vitamin C; vegetable oils (sunflower and olive) (40 %), non-citrus fruits (10 %), and nuts and seeds (8 %) for vitamin E; root vegetables (carrots) (82 %) for alpha-carotene; green leafy (28 %), root (24 %) and fruiting vegetables (22 %) for beta-carotene; fruiting vegetables (fresh tomato) (72 %) for lycopene; green leafy vegetables (64 %) for lutein; citrus fruits (68 %) for beta-cryptoxanthin; citrus fruits (43 %) and green leafy vegetables (20 %) for zeaxanthin. In conclusion, the main food sources of nutrients with redox properties have been identified in a Mediterranean country. This could provide an insight into the interpretation of epidemiological studies investigating the role of diet in health and disease.