Comparison between 16S rRNA and shotgun sequencing in colorectal cancer, advanced colorectal lesions, and healthy human gut microbiota.

BACKGROUND: Gut dysbiosis has been associated with colorectal cancer (CRC), the third most prevalent cancer in the world. This study compares microbiota taxonomic and abundance results obtained by 16S rRNA gene sequencing (16S) and whole shotgun metagenomic sequencing to investigate their reliability for bacteria profiling. The experimental design included 156 human stool samples from healthy controls, advanced (high-risk) colorectal lesion patients (HRL), and CRC cases, with each sample sequenced using both 16S and shotgun methods. We thoroughly compared both sequencing technologies at the species, genus, and family annotation levels, the abundance differences in these taxa, sparsity, alpha and beta diversities, ability to train prediction models, and the similarity of the microbial signature derived from these models. RESULTS: As expected, the results showed that 16S detects only part of the gut microbiota community revealed by shotgun, although some genera were only profiled by 16S. The 16S abundance data was sparser and exhibited lower alpha diversity. In lower taxonomic ranks, shotgun and 16S highly differed, partially due to a disagreement in reference databases. When considering only shared taxa, the abundance was positively correlated between the two strategies. We also found a moderate correlation between the shotgun and 16S alpha-diversity measures, as well as their PCoAs. Regarding the machine learning models, only some of the shotgun models showed some degree of predictive power in an independent test set, but we could not demonstrate a clear superiority of one technology over the other. Microbial signatures from both sequencing techniques revealed taxa previously associated with CRC development, e.g., Parvimonas micra. CONCLUSIONS: Shotgun and 16S sequencing provide two different lenses to examine microbial communities. While we have demonstrated that they can unravel common patterns (including microbial signatures), shotgun often gives a more detailed snapshot than 16S, both in depth and breadth. Instead, 16S will tend to show only part of the picture, giving greater weight to dominant bacteria in a sample. Therefore, we recommend choosing one or another sequencing technique before launching a study. Specifically, shotgun sequencing is preferred for stool microbiome samples and in-depth analyses, while 16S is more suitable for tissue samples and studies with targeted aims.

Performance of a Shotgun Prediction Model for Colorectal Cancer When Using 16S rRNA Sequencing Data.

Colorectal cancer (CRC), the third most common cancer globally, has shown links to disturbed gut microbiota. While significant efforts have been made to establish a microbial signature indicative of CRC using shotgun metagenomic sequencing, the challenge lies in validating this signature with 16S ribosomal RNA (16S) gene sequencing. The primary obstacle is reconciling the differing outputs of these two methodologies, which often lead to divergent statistical models and conclusions. In this study, we introduce an algorithm designed to bridge this gap by mapping shotgun-derived taxa to their 16S counterparts. This mapping enables us to assess the predictive performance of a shotgun-based microbiome signature using 16S data. Our results demonstrate a reduction in performance when applying the 16S-mapped taxa in the shotgun prediction model, though it retains statistical significance. This suggests that while an exact match between shotgun and 16S data may not yet be feasible, our approach provides a viable method for comparative analysis and validation in the context of CRC-associated microbiome research.

Post-polypectomy colonoscopy surveillance: Can we improve the diagnostic yield?

Although adenomas and serrated polyps are the preneoplastic lesions of colorectal cancer, only few of them will eventually progress to cancer. This review provides a comprehensive overview of the present and future of post-polypectomy colonoscopy surveillance. Post-polypectomy surveillance guidelines have recently been updated and all share the aim towards more selective and less frequent surveillance. We have examined these current guidelines and compared the recommendations of each of them. To improve the diagnostic yield of post-polypectomy surveillance it is important to find predictors of metachronous polyps that better identify high-risk individuals of developing advanced neoplasia. For this reason, we have also conducted a literature review of the molecular biomarkers of metachronous advanced colorectal polyps. Finally, we have discussed future directions of post-polypectomy surveillance and identified possible strategies to improve the use of endoscopic resources with the COVID-19 pandemic.

Polygenic risk score across distinct colorectal cancer screening outcomes: from premalignant polyps to colorectal cancer.

BACKGROUND: Different risk-based colorectal cancer (CRC) screening strategies, such as the use of polygenic risk scores (PRS), have been evaluated to improve effectiveness of these programs. However, few studies have previously assessed its usefulness in a fecal immunochemical test (FIT)-based screening study. METHODS: A PRS of 133 single nucleotide polymorphisms was assessed for 3619 participants: population controls, screening controls, low-risk lesions (LRL), intermediate-risk (IRL), high-risk (HRL), CRC screening program cases, and clinically diagnosed CRC cases. The PRS was compared between the subset of cases (n = 648; IRL+HRL+CRC) and controls (n = 956; controls+LRL) recruited within a FIT-based screening program. Positive predictive values (PPV), negative predictive values (NPV), and the area under the receiver operating characteristic curve (aROC) were estimated using cross-validation. RESULTS: The overall PRS range was 110-156. PRS values increased along the CRC tumorigenesis pathway (Mann-Kendall P value 0.007). Within the screening subset, the PRS ranged 110-151 and was associated with higher risk-lesions and CRC risk (ORD10vsD1 1.92, 95% CI 1.22-3.03). The cross-validated aROC of the PRS for cases and controls was 0.56 (95% CI 0.53-0.59). Discrimination was equal when restricted to positive FIT (aROC 0.56), but lower among negative FIT (aROC 0.55). The overall PPV among positive FIT was 0.48. PPV were dependent on the number of risk alleles for positive FIT (PPVp10-p90 0.48-0.57). CONCLUSIONS: PRS plays an important role along the CRC tumorigenesis pathway; however, in practice, its utility to stratify the general population or as a second test after a FIT positive result is still doubtful. Currently, PRS is not able to safely stratify the general population since the improvement on PPV values is scarce.

The use of faecal immunochemical testing in the decision-making process for the endoscopic investigation of iron deficiency anaemia.

Background Blood loss from the gastrointestinal (GI) tract is the most common cause of iron deficiency anaemia (IDA) in adult men and postmenopausal women. Gastroduodenal endoscopy (GDE) and colonoscopy are frequently recommended, despite uncertainty regarding the coexistence of lesions in the upper and lower GI tract. The faecal immunochemical test (FIT) measures the concentration of faecal haemoglobin (f-Hb) originating only from the colon or rectum. We aimed to assess whether the FIT was able to select the best endoscopic procedure for detecting the cause of IDA. Methods A prospective study of 120 men and postmenopausal women referred for a diagnostic study of IDA were evaluated with an FIT, GDE and colonoscopy. The endoscopic finding of a significant upper lesion (SUL) or a significant bowel lesion (SBL) was considered to be the cause of the IDA. Results The diagnoses were 35.0% SUL and 20.0% SBL, including 13.3% GI cancer. In the multivariate analysis, the concentration of blood haemoglobin (b-Hb) <9 g/dL (OR: 2.60; 95% CI 1.13-6.00; p = 0.025) and non-steroidal anti-inflammatory drugs NSAIDs (2.56; 1.13-5.88; p = 0.024) were associated with an SUL. Age (0.93; 0.88-0.99; p = 0.042) and f-Hb ≥ 15 µg Hb/g faeces (38.53; 8.60-172.50; p < 0.001) were associated with an SBL. A "FIT plus gastroscopy" strategy, in which colonoscopy is performed only when f-Hb ≥15 µg Hb/g faeces, would be able to detect 92.4% of lesions and be 100% accurate in the detection of cancer while avoiding 71.6% of colonoscopies. Conclusions The FIT is an accurate method for selecting the best endoscopy study for the evaluation of IDA. An FIT-based strategy is more cost-effective than the current bidirectional endoscopy-based strategy and could improve endoscopic resource allocation.

Risk of colorectal cancer in users of bisphosphonates: analysis of population-based electronic health records.

The use of bisphosphonates has been associated with a decrease in the risk of colorectal cancer (CRC) in observational studies, but with controversial results and difficult to interpret because of routine concomitant use of calcium and vitamin D. We aimed to assess the association between CRC risk and outpatient exposure to antiosteoporotic drugs using a large cohort with prescription data in Catalonia. A case-control study was performed using the Information System for Development of Primary Care Research (SIDIAP) which is a primary care medical record database that has linked data on reimbursed medication. The study included 25,836 cases with an incident diagnosis of CRC between 2010 and 2015 and 129,117 matched controls by age (± 5 years), sex and healthcare region. A multivariable model was built adjusting for known risk factors and comorbidities that were significantly associated to CRC in the dataset, and a propensity score for bisphosphonates. Tests for interaction for multiple drug use and stratified analysis for tumour location were prospectively planned. Overall 18,230 individuals (11.5%) were users of bisphosphonates. A significant but modest protective effect on CRC was observed for bisphosphonates (OR 0.95, 95% CI 0.91-0.99), that was no longer significant when adjusted for calcium and vitamin D (OR 0.98, 95% CI 0.93-1.03). Bisphosphonates, however, showed a dose-response effect with duration of use even when adjusted for calcium and vitamin D (OR for use > 40 months: 0.90, 95% CI 0.81-1.00, P value for trend: 0.018). The use of bisphosphonates was associated with a modest decrease in the risk of CRC, but this effect was essentially explained by concomitant use of calcium or vitamin D. The observed protective effect was stronger for long durations of use, which deserves further study.

Survival of patients with cirrhosis and acute peptic ulcer bleeding compared with variceal bleeding using current first-line therapies.

The presence of cirrhosis increases the mortality of patients with peptic ulcer bleeding (PUB). Both acute variceal bleeding (AVB) and PUB are associated with substantial mortality in cirrhosis. This multicenter cohort study was performed to assess whether the mortality of patients with cirrhosis with PUB is different from that of those with AVB. Patients with cirrhosis and acute gastrointestinal bleeding were consecutively included and treated with somatostatin and proton pump inhibitor infusion from admission and with antibiotic prophylaxis. Emergency endoscopy with endoscopic therapy was performed within the first 6 hours. 646 patients with AVB and 144 with PUB were included. There were baseline differences between groups, such as use of gastroerosive drugs or ß-blockers. Child-Pugh and Model for End-Stage Liver Disease MELD scores were similar. Further bleeding was more frequent in the AVB group than those in the PUB group (18% vs. 10%; odds ratio [OR] = 0.50; 95% confidence interval [CI] = 0.29-0.88). However, mortality risk at 45 days was similar in both groups (19% in the AVB group vs. 17% in the PUB group; OR = 0.85; 95% CI = 0.55-1.33; P = 0.48). Different parameters, such as Child-Pugh score, acute kidney injury, acute on chronic liver failure, or presence of shock or bacterial infection, but not the cause of bleeding, were related to the risk of death. Only 2% of the PUB group versus 3% of the AVB group died with uncontrolled bleeding (P = 0.39), whereas the majority of patients in either group died from liver failure or attributed to other comorbidities. CONCLUSION: Using current first-line therapy, patients with cirrhosis and acute peptic ulcer bleeding have a similar survival than those with variceal bleeding. The risk of further bleeding is higher in patients with variceal hemorrhage. However, few patients in both groups died from uncontrolled bleeding, rather the cause of death was usually related to liver failure or comorbidities. (Hepatology 2018;67:1458-1471).

Spontaneous intramural esophageal dissection: an unusual onset of eosinophilic esophagitis.

A 35-year-old man, with a history of rhinitis, eczema and a dubious achalasia was admitted due to chest pain and sialorrhea. Upper endoscopy showed a little hole and a narrowing of the distal esophagus. A CT-scan with oral contrast exposed a discontinuity of the lumen of the middle third of the esophagus and a dissection of submucosal space 16 cm long. The patient recovered after parenteral nutrition. After four months, an esophageal endoscopic showed transient whitish exudates, longitudinal furrows and esophageal lacerations. The biopsies illustrated significant eosinophilic inflammation, eosinophilic microabscesses and basal cell hyperplasia.

Endoscopic band ligation without resection in selected patients for small and superficial upper gastrointestinal tract lesions.

BACKGROUND AND AIM: The aim of this study was to evaluate the efficacy of endoscopic band ligation (EBL) in carefully selected patients who would benefit from this method of resection. METHODS: Patients with early upper gastrointestinal and small (< 15 mm) lesions treated with EBL (Duette® Multi-Band Mucosectomy) were prospectively recruited and retrospectively analyzed between 2010 and 2015. All cases were discussed in a multidisciplinary cancer committee and it was concluded that, owing to patient conditions, surgery was not possible and that not conducting histology would not change the clinical management. A first endoscopic control with biopsies was planned at 4-8 weeks. If there was no persistence of the lesion, new controls were programmed at 6 and 12 months. RESULTS: The group (n = 12) included 5 esophagus lesions (adenosquamous carcinoma, n = 1; carcinoma squamous, n = 2; adenocarcinoma, n = 2); 4 gastric lesions (high grade dysplasia, n = 1; adenocarcinoma, n = 2; neuroendocrine tumor [NET], n = 1), and 3 duodenal lesions (NETs) (n = 3). The mean tumor diameter was 9.6 ± 2.8 mm (range 4-15). Only one minor adverse event was described. At first follow-up (4-8 weeks), there was 91.6% and 75% of endoscopic and histological remission, respectively. At 6-month follow-up there was 70% of both endoscopic remission and negative biopsies. And at 12 months, there was 100% and 75% of endoscopic and histological remission, respectively. Persisting lesions were T1 cancers. The median follow-up was 30.6 months. CONCLUSION: EBL without resection is an easy and safe technique that should be considered in patients with multiple morbidities and small superficial UGI lesions.

Effectiveness and Acceptability of Targeted Text Message Reminders in Colorectal Cancer Screening: Randomized Controlled Trial (M-TICS Study).

BACKGROUND: Mobile phone-based SMS text message reminders have the potential to improve colorectal cancer screening participation rates. OBJECTIVE: This study assessed the effectiveness and acceptability of adding targeted SMS text message reminders to the standard procedure for those who picked up but did not return their screening kit at the pharmacy within 14 days in a colorectal cancer screening program in Catalonia, Spain. METHODS: We performed a randomized control trial among individuals who picked up a fecal immunochemical test (FIT) kit for colorectal cancer screening at the pharmacy but did not return it within 14 days. The intervention group (n=4563) received an SMS text message reminder on the 14th day of kit pick up and the control group (n=4806) received no reminder. A 30-day reminder letter was sent to both groups if necessary. The main primary outcome was the FIT completion rate within 30, 60, and 126 days from FIT kit pick up (intention-to-treat analysis). A telephone survey assessed the acceptability and appropriateness of the intervention. The cost-effectiveness of adding an SMS text message reminder to FIT completion was also performed. RESULTS: The intervention group had higher FIT completion rates than the control group at 30 (64.2% vs 53.7%; P<.001), 60 (78.6% vs 72.0%; P<.001), and 126 (82.6% vs 77.7%; P<.001) days. Participation rates were higher in the intervention arm independent of sex, age, socioeconomic level, and previous screening behavior. A total of 339 (89.2%) interviewees considered it important and useful to receive SMS text message reminders for FIT completion and 355 (93.4%) preferred SMS text messages to postal letters. We observed a reduction of US $2.4 per participant gained in the intervention arm for invitation costs compared to the control arm. CONCLUSIONS: Adding an SMS text message reminder to the standard procedure significantly increased FIT kit return rates and was a cost-effective strategy. SMS text messages also proved to be an acceptable and appropriate communication channel for cancer screening programs. TRIAL REGISTRATION: ClinicalTrials.gov NCT04343950; https://www.clinicaltrials.gov/study/NCT04343950. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.1371/journal.pone.0245806.

Diagnostic Performance of a Fecal Immunochemical Test-Based Colorectal Cancer Screening Program According to Ambient Temperature and Humidity.

Exposure of the fecal immunochemical test (FIT) to different ambient temperatures and humidity is unavoidable in population-based screening programs in Southern European countries, and it could lead to a decrease in target colorectal lesions. The objective was to evaluate the effect of ambient temperature and humidity on the FIT sensitivity in a population-based screening program for colorectal cancer (CRC) using an ecological design. The retrospective cohort included individuals aged 50−69 years who participated in CRC screening (Barcelona) from 2010−2015, and were followed until 2017 to identify interval CRCs. The positivity rate, and detection rates for advanced polyps and CRC were compared according to ambient temperature, humidity, and quarters of the year. A positive FIT was defined as the detection of ≥20 µg Hb/g in feces. The monthly ambient temperature and humidity were recorded on the day that the FIT was performed. In total, 92,273 FIT results from 53,860 participants were analyzed. The FIT positivity rate was lower at >24 °C than at ≤24 °C (p = 0.005) but was not affected by humidity. The temperature's impact on positivity did not lead to a decrease in the FIT detection rate for advanced neoplasia or the interval cancer detection rate in a program where the samples were refrigerated until the analysis and screening invitations were discontinued in July and August.

Transcriptome-Wide Association Study for Inflammatory Bowel Disease Reveals Novel Candidate Susceptibility Genes in Specific Colon Subsites and Tissue Categories.

BACKGROUND AND AIMS: Genome-wide association studies [GWAS] for inflammatory bowel disease [IBD] have identified 240 risk variants. However, the benefit of understanding the genetic architecture of IBD remains to be exploited. Transcriptome-wide association studies [TWAS] associate gene expression with genetic susceptibility to disease, providing functional insight into risk loci. In this study, we integrate relevant datasets for IBD and perform a TWAS to nominate novel genes implicated in IBD genetic susceptibility. METHODS: We applied elastic net regression to generate gene expression prediction models for the University of Barcelona and University of Virginia RNA sequencing project [BarcUVa-Seq] and correlated expression and disease association research [CEDAR] datasets. Together with Genotype-Tissue Expression project [GTEx] data, and GWAS results from about 60 000 individuals, we employed Summary-PrediXcan and Summary-MultiXcan for single and joint analyses of TWAS results, respectively. RESULTS: BarcUVa-Seq TWAS revealed 39 novel genes whose expression in the colon is associated with IBD genetic susceptibility. They included expression markers for specific colon cell types. TWAS meta-analysis including all tissues/cell types provided 186 novel candidate susceptibility genes. Additionally, we identified 78 novel susceptibility genes whose expression is associated with IBD exclusively in immune (N = 19), epithelial (N = 25), mesenchymal (N = 22) and neural (N = 12) tissue categories. Associated genes were involved in relevant molecular pathways, including pathways related to known IBD therapeutics, such as tumour necrosis factor signalling. CONCLUSION: These findings provide insight into tissue-specific molecular processes underlying IBD genetic susceptibility. Associated genes could be candidate targets for new therapeutics and should be prioritized in functional studies.

Meta-Analysis and Validation of a Colorectal Cancer Risk Prediction Model Using Deep Sequenced Fecal Metagenomes.

The gut microbiome is a potential modifiable risk factor for colorectal cancer (CRC). We re-analyzed all eight previously published stool sequencing data and conducted an MWAS meta-analysis. We used cross-validated LASSO predictive models to identify a microbiome signature for predicting the risk of CRC and precancerous lesions. These models were validated in a new study, Colorectal Cancer Screening (COLSCREEN), including 156 participants that were recruited in a CRC screening context. The MWAS meta-analysis identified 95 bacterial species that were statistically significantly associated with CRC (FDR < 0.05). The LASSO CRC predictive model obtained an area under the receiver operating characteristic curve (aROC) of 0.81 (95%CI: 0.78−0.83) and the validation in the COLSCREEN dataset was 0.75 (95%CI: 0.66−0.84). This model selected a total of 32 species. The aROC of this CRC-trained model to predict precancerous lesions was 0.52 (95%CI: 0.41−0.63). We have identified a signature of 32 bacterial species that have a good predictive accuracy to identify CRC but not precancerous lesions, suggesting that the identified microbes that were enriched or depleted in CRC are merely a consequence of the tumor. Further studies should focus on CRC as well as precancerous lesions with the intent to implement a microbiome signature in CRC screening programs.

Evaluating the Potential of Polygenic Risk Score to Improve Colorectal Cancer Screening.

BACKGROUND: Colorectal cancer has high incidence and associated mortality worldwide. Screening programs are recommended for men and women over 50. Intermediate screens such as fecal immunochemical testing (FIT) select patients for colonoscopy with suboptimal sensitivity. Additional biomarkers could improve the current scenario. METHODS: We included 2,893 individuals with a positive FIT test. They were classified as cases when a high-risk lesion for colorectal cancer was detected after colonoscopy, whereas the control group comprised individuals with low-risk or no lesions. 65 colorectal cancer risk genetic variants were genotyped. Polygenic risk score (PRS) and additive models for risk prediction incorporating sex, age, FIT value, and PRS were generated. RESULTS: Risk score was higher in cases compared with controls [per allele OR = 1.04; 95% confidence interval (CI), 1.02-1.06; P < 0.0001]. A 2-fold increase in colorectal cancer risk was observed for subjects in the highest decile of risk alleles (≥65), compared with those in the first decile (≤54; OR = 2.22; 95% CI, 1.59-3.12; P < 0.0001). The model combining sex, age, FIT value, and PRS reached the highest accuracy for identifying patients with a high-risk lesion [cross-validated area under the ROC curve (AUROC): 0.64; 95% CI, 0.62-0.66]. CONCLUSIONS: This is the first investigation analyzing PRS in a two-step colorectal cancer screening program. PRS could improve current colorectal cancer screening, most likely for higher at-risk subgroups. However, its capacity is limited to predict colorectal cancer risk status and should be complemented by additional biomarkers. IMPACT: PRS has capacity for risk stratification of colorectal cancer suggesting its potential for optimizing screening strategies alongside with other biomarkers.

Future Prospects of Colorectal Cancer Screening: Characterizing Interval Cancers.

Tumors that are not detected by screening tests are known as interval cancers and are diagnosed clinically after a negative result in the screening episode but before the next screening invitation. Clinical characteristics associated with interval colorectal cancers have been studied, but few molecular data are available that describe interval colorectal cancers. A better understanding of the clinical and biological characteristics associated with interval colorectal cancer may provide new insights into how to prevent this disease more effectively. This review aimed to summarize the current literature concerning interval colorectal cancer and its epidemiological, clinical, and molecular features.

Positive impact of a faecal-based screening programme on colorectal cancer mortality risk.

INTRODUCTION: The effectiveness of colorectal cancer (CRC) screening programs is directly related to participation and the number of interval CRCs. The objective was to analyse specific-mortality in a cohort of individuals invited to a CRC screening program according to type of CRC diagnosis (screen-detected cancers, interval cancers, and cancers among the non-uptake group). MATERIAL AND METHODS: Retrospective cohort that included invitees aged 50-69 years of a CRC screening program (target population of 85,000 people) in Catalonia (Spain) from 2000-2015 with mortality follow-up until 2020. A screen-detected CRC was a cancer diagnosed after a positive faecal occult blood test (guaiac or immunochemical); an interval cancer was a cancer diagnosed after a negative test result and before the next invitation to the program (≤24 months); a non-uptake cancer was a cancer in subjects who declined screening. RESULTS: A total of 624 people were diagnosed with CRC (n = 265 screen-detected, n = 103 interval cancers, n = 256 non-uptake). In the multivariate analysis, we observed a 74% increase in mortality rate in the group with interval CRC compared to screen-detected CRC adjusted for age, sex, location and stage (HR: 1.74%, 95% CI:1.08-2.82, P = 0.02). These differences were found even when we restricted for advanced-cancers participants. In the stratified analysis for type of faecal occult blood test, a lower mortality rate was only observed among FIT screen-detected CRCs. CONCLUSION: CRC screening with the FIT was associated with a significant reduction in CRC mortality.

Text messaging as a tool to improve cancer screening programs (M-TICS Study): A randomized controlled trial protocol.

BACKGROUND: Short message service (SMS) based interventions are widely used in healthcare and have shown promising results to improve cancer screening programs. However, more research is still needed to implement SMS in the screening process. We present a study protocol to assess the impact on health and economics of three targeted SMS-based interventions in population-based cancer screening programs. METHODS/DESIGN: The M-TICs study is a randomized controlled trial with a formal process evaluation. Participants aged 50-69 years identified as eligible from the colorectal cancer (CRC) and breast cancer (BC) screening program of the Catalan Institute of Oncology (Catalonia, Spain) will be randomly assigned to receive standard invitation procedure (control group) or SMS-based intervention to promote participation. Two interventions will be conducted in the CRC screening program: 1) Screening invitation reminder: Those who do not participate in the CRC screening within 6 weeks of invite will receive a reminder (SMS or letter); 2) Reminder to complete and return fecal immunochemical test (FIT) kit: SMS reminder versus no intervention to individuals who have picked up a FIT kit at the pharmacy and they have not returned it after 14 days. The third intervention will be performed in the BC screening program. Women who had been screened previously will receive an SMS invitation or a letter invitation to participate in the screening. As a primary objective we will assess the impact on participation for each intervention. The secondary objectives will be to analyze the cost-effectiveness of the interventions and to assess participants' perceptions. EXPECTED RESULTS: The results from this randomized controlled trial will provide important empirical evidence for the use of mobile phone technology as a tool for improving population-based cancer screening programs. These results may influence the cancer screening invitation procedure in future routine practice. TRIAL REGISTRATION: Registry: NCT04343950 (04/09/2020); clinicaltrials.gov.

Proton-pump inhibitors are associated with a high false-positivity rate in faecal immunochemical testing.

BACKGROUND: False-positivity rates in faecal immunochemical test (FIT) can be affected by drug exposure. We aimed to assess the association between proton pump inhibitors (PPI) consumption and false positive (FP) results in a colorectal cancer (CRC) screening programme using electronic prescription records. METHODS: A retrospective cohort study within a population-based screening program for CRC from 2010 to 2016 was performed. Participants with a conclusive FIT result and with prescription electronic data were included. An FP result was defined as having a positive FIT (≥ 20 µg haemoglobin/g faeces) and a follow-up colonoscopy without intermediate or high-risk lesions or CRC. Screening data were anonymously linked to the public data analysis program for health research and innovation (PADRIS) database that recorded patient diseases history and reimbursed medication. PPI exposure was defined as having retrieved at least one dispensation of PPI three months prior to the FIT. RESULTS: A total of 89,199 tests (of 46,783 participants) were analysed, 4824 (5.4%) tested positive and the proportion of FP was 53.5%. Overall, 17,544 participants (19.7%) were PPI users prior to FIT performance. PPI exposure increased the probability of obtaining an FP FIT result from 50.4 to 63.3% (adjusted OR 1.39; 95% CI 1.18-1.65). Nonsteroidal anti-inflammatory drugs, acetylsalicylic acid, antibiotics, and laxatives were also associated with an FP result. The effect of PPI was independent and showed a synergistic interaction with nonsteroidal anti-inflammatory drugs. CONCLUSION: PPIs increase FIT positivity at the expense of FP results. The recommendation to avoid their use before FIT performance could reduce up to 3% of colonoscopies and 9% of FP results.

Genetic Effects on Transcriptome Profiles in Colon Epithelium Provide Functional Insights for Genetic Risk Loci.

BACKGROUND & AIMS: The association of genetic variation with tissue-specific gene expression and alternative splicing guides functional characterization of complex trait-associated loci and may suggest novel genes implicated in disease. Here, our aims were as follows: (1) to generate reference profiles of colon mucosa gene expression and alternative splicing and compare them across colon subsites (ascending, transverse, and descending), (2) to identify expression and splicing quantitative trait loci (QTLs), (3) to find traits for which identified QTLs contribute to single-nucleotide polymorphism (SNP)-based heritability, (4) to propose candidate effector genes, and (5) to provide a web-based visualization resource. METHODS: We collected colonic mucosal biopsy specimens from 485 healthy adults and performed bulk RNA sequencing. We performed genome-wide SNP genotyping from blood leukocytes. Statistical approaches and bioinformatics software were used for QTL identification and downstream analyses. RESULTS: We provided a complete quantification of gene expression and alternative splicing across colon subsites and described their differences. We identified thousands of expression and splicing QTLs and defined their enrichment at genome-wide regulatory regions. We found that part of the SNP-based heritability of diseases affecting colon tissue, such as colorectal cancer and inflammatory bowel disease, but also of diseases affecting other tissues, such as psychiatric conditions, can be explained by the identified QTLs. We provided candidate effector genes for multiple phenotypes. Finally, we provided the Colon Transcriptome Explorer web application. CONCLUSIONS: We provide a large characterization of gene expression and splicing across colon subsites. Our findings provide greater etiologic insight into complex traits and diseases influenced by transcriptomic changes in colon tissue.