Reliable multiplex generation of pooled induced pluripotent stem cells.

Reprogramming somatic cells into pluripotent stem cells (iPSCs) enables the study of systems in vitro. To increase the throughput of reprogramming, we present induction of pluripotency from pooled cells (iPPC)-an efficient, scalable, and reliable reprogramming procedure. Using our deconvolution algorithm that employs pooled sequencing of single-nucleotide polymorphisms (SNPs), we accurately estimated individual donor proportions of the pooled iPSCs. With iPPC, we concurrently reprogrammed over one hundred donor lymphoblastoid cell lines (LCLs) into iPSCs and found strong correlations of individual donors' reprogramming ability across multiple experiments. Individual donors' reprogramming ability remains consistent across both same-day replicates and multiple experimental runs, and the expression of certain immunoglobulin precursor genes may impact reprogramming ability. The pooled iPSCs were also able to differentiate into cerebral organoids. Our procedure enables a multiplex framework of using pooled libraries of donor iPSCs for downstream research and investigation of in vitro phenotypes.

FACS-Based Sequencing Approach to Evaluate Cell Type to Genotype Associations Using Cerebral Organoids.

Recent technological developments have led to widespread applications of large-scale transcriptomics-based sequencing methods to identify genotype-to-cell type associations. Here we describe a fluorescence-activated cell sorting (FACS)-based sequencing method to utilize CRISPR/Cas9 edited mosaic cerebral organoids to identify or validate genotype-to-cell type associations. Our approach is high-throughput and quantitative and uses internal controls to enable comparisons of the results across different antibody markers and experiments.

Modeling of mitochondrial genetic polymorphisms reveals induction of heteroplasmy by pleiotropic disease locus 10398A>G.

Mitochondrial (MT) dysfunction has been associated with several neurodegenerative diseases including Alzheimer's disease (AD). While MT-copy number differences have been implicated in AD, the effect of MT heteroplasmy on AD has not been well characterized. Here, we analyzed over 1800 whole genome sequencing data from four AD cohorts in seven different tissue types to determine the extent of MT heteroplasmy present. While MT heteroplasmy was present throughout the entire MT genome for blood samples, we detected MT heteroplasmy only within the MT control region for brain samples. We observed that an MT variant 10398A>G (rs2853826) was significantly associated with overall MT heteroplasmy in brain tissue while also being linked with the largest number of distinct disease phenotypes of all annotated MT variants in MitoMap. Using gene-expression data from our brain samples, our modeling discovered several gene networks involved in mitochondrial respiratory chain and Complex I function associated with 10398A>G. The variant was also found to be an expression quantitative trait loci (eQTL) for the gene MT-ND3. We further characterized the effect of 10398A>G by phenotyping a population of lymphoblastoid cell-lines (LCLs) with and without the variant allele. Examination of RNA sequence data from these LCLs reveal that 10398A>G was an eQTL for MT-ND4. We also observed in LCLs that 10398A>G was significantly associated with overall MT heteroplasmy within the MT control region, confirming the initial findings observed in post-mortem brain tissue. These results provide novel evidence linking MT SNPs with MT heteroplasmy and open novel avenues for the investigation of pathomechanisms that are driven by this pleiotropic disease associated loci.

oFlowSeq: a quantitative approach to identify protein coding mutations affecting cell type enrichment using mosaic CRISPR-Cas9 edited cerebral organoids.

Cerebral organoids are comprised of diverse cell types found in the developing human brain, and can be leveraged in the identification of critical cell types perturbed by genetic risk variants in common, neuropsychiatric disorders. There is great interest in developing high-throughput technologies to associate genetic variants with cell types. Here, we describe a high-throughput, quantitative approach (oFlowSeq) by utilizing CRISPR-Cas9, FACS sorting, and next-generation sequencing. Using oFlowSeq, we found that deleterious mutations in autism-associated gene KCTD13 resulted in increased proportions of Nestin+ cells and decreased proportions of TRA-1-60+ cells within mosaic cerebral organoids. We further identified that a locus-wide CRISPR-Cas9 survey of another 18 genes in the 16p11.2 locus resulted in most genes with > 2% maximum editing efficiencies for short and long indels, suggesting a high feasibility for an unbiased, locus-wide experiment using oFlowSeq. Our approach presents a novel method to identify genotype-to-cell type imbalances in an unbiased, high-throughput, quantitative manner.

Esophageal Columnar Metaplasia in Childhood: A Population-Based Case Series Analysis.

BACKGROUND: Adults with Barrett's esophagus (BE) are often entered into surveillance for esophageal adenocarcinoma (EAC), although cancer risk is relatively low. BE can be detected in children (< 16 years). Little is known about the epidemiology of pediatric BE, and it is unclear what the optimal surveillance regimes are in children. AIM: To evaluate the demographic and clinical characteristics, and future neoplastic progression risk in all pediatric BE patients diagnosed in Northern Ireland between 1993 and 2010. METHODS: Data from the population-based Northern Ireland BE register were matched to the Northern Ireland Cancer Registry for EAC outcomes until end 2013. Age-adjusted incidence of pediatric BE was calculated, and characteristics between pediatric and adult BE patients compared using Chi-square tests. RESULTS: Over 18 years, 42 pediatric BE patients (< 16 years) were identified, equivalent to an age-adjusted incidence of < 2 per 100,000 children. There was a clear age differential, with BE incidence increasing with age within the pediatric population. The majority (85.7%) of patients were male, a significantly higher male/female ratio than adult BE patients (p < 0.001). No pediatric BE patients progressed to high-grade dysplasia (HGD) or EAC, although the eldest patient was aged 34 years by the end of follow-up. CONCLUSIONS: This is the largest series of pediatric BE ever reported. It demonstrates that pediatric BE is rare. The male preponderance of this condition is more apparent in childhood compared with adult cases. No children developed HGD/EAC during follow-up, suggesting that regular surveillance is not required, at least until adulthood.

Experiences of accessing and using breast cancer services in Vietnam: a descriptive qualitative study.

OBJECTIVES: To understand, describe and analyse the experiences of women with breast cancer in Vietnam when accessing and using breast cancer services. DESIGN: Descriptive qualitative study. Women were interviewed about their experiences from the first time they became aware of symptoms or changes to their body through treatment and post-treatment. This study is the first descriptive study on breast cancer in Vietnam from the perspective of women with a breast cancer diagnosis. PARTICIPANTS: Women (n=13) who had completed or were still receiving treatment for breast cancer, purposively recruited from the north and south of Vietnam. RESULTS: An analysis of the experiences of women with breast cancer in Vietnam revealed a lack of awareness and knowledge about breast cancer and symptoms. Family and social support were described as key factors influencing whether a woman accesses and uses breast cancer services. Cost of treatment and out-of-pocket expenditures limited access to services and resulted in significant financial challenges for women and their families. CONCLUSIONS: Vietnam has made huge strides in improving cancer care, and is tackling a complex and expanding public health challenge, however, there are a number of areas requiring strengthening and future research. While Vietnam has successfully expanded social health insurance coverage, changes that increase the percentage of costs covered for specific treatments, such as chemotherapy or radiotherapy, could benefit women and their families.

Fusobacterium nucleatum in the Colorectum and Its Association with Cancer Risk and Survival: A Systematic Review and Meta-analysis.

BACKGROUND: The gut microbiome, in particular Fusobacterium nucleatum, has been reported to play a role in colorectal cancer development and in patient prognosis. We aimed to perform a systematic review and meta-analysis of published studies to assess the prevalence of F. nucleatum in colorectal tumors and evaluate the association between F. nucleatum and colorectal cancer development and prognosis. METHODS: MEDLINE, EMBASE, and Web of Science databases were systematically searched for studies published until January 2019. Random effects meta-analyses were used to assess the prevalence of F. nucleatum in patients with colorectal cancer or tissues relative to controls and survival in F. nucleatum-positive versus -negative patients. RESULTS: Forty-five relevant articles were identified. Meta-analyses indicated higher odds of F. nucleatum being present in colorectal tissue samples from patients with colorectal cancer [n = 6 studies, pooled OR = 10.06; 95% confidence intervals (CI), 4.48-22.58] and individuals with colorectal polyps (n = 5 studies, pooled OR = 1.83; 95% CI, 1.07-3.16) compared with healthy controls. Similar results were apparent in fecal samples, and when comparing tumor with adjacent normal tissue. Meta-analyses indicated poorer survival in patients with colorectal cancer with high versus low F. nucleatum abundance (n = 5 studies, pooled HR = 1.87; 95% CI, 1.12-3.11). CONCLUSIONS: A consistent increase in the prevalence and/or abundance of F. nucleatum in colorectal cancer tissue and fecal samples compared with controls was apparent. High abundance of F. nucleatum in colorectal tumors was also associated with poorer overall survival. IMPACT: F. nucleatum could be useful as a diagnostic and prognostic marker for colorectal cancer or as a treatment target.

The association between self-reported poor oral health and gastrointestinal cancer risk in the UK Biobank: A large prospective cohort study.

Background: Controversy remains as to whether poor oral health is independently associated with gastrointestinal cancers, due to potential confounding by smoking, alcohol and poor nutrition. The aim of this study was to investigate the association between oral health conditions and gastrointestinal cancer risk. Methods: Data from the large, prospective UK Biobank cohort, which includes n = 475,766 participants, were analysed. Cox proportional hazard models were applied to estimate the relationship between gastrointestinal cancer risk and self-reported poor oral health (defined as painful gums, bleeding gums and/or having loose teeth), adjusting for confounders. Results: During an average six years of follow-up, n = 4069 gastrointestinal cancer cases were detected, of which 13% self-reported poor oral health. Overall, there was no association between self-reported poor oral health and risk of gastrointestinal cancer detected (hazard ratio 0.97, 95% confidence interval 0.88-1.07). In site-specific analysis, an increased risk of hepatobiliary cancers was observed in those with self-reported poor oral health (hazard ratio 1.32, 95% confidence interval 0.95-1.80), which was stronger for hepatocellular carcinoma (hazard ratio 1.75, 95% confidence interval 1.04-2.92). Conclusion: Overall there was no association between self-reported poor oral health and gastrointestinal cancer risk. However, there was a suggestion of an increased risk of hepatobiliary cancer, specifically hepatocellular carcinoma.

Diabetes in relation to Barrett's esophagus and adenocarcinomas of the esophagus: A pooled study from the International Barrett's and Esophageal Adenocarcinoma Consortium.

BACKGROUND: Diabetes is positively associated with various cancers, but its relationship with tumors of the esophagus/esophagogastric junction remains unclear. METHODS: Data were harmonized across 13 studies in the International Barrett's and Esophageal Adenocarcinoma Consortium, comprising 2309 esophageal adenocarcinoma (EA) cases, 1938 esophagogastric junction adenocarcinoma (EGJA) cases, 1728 Barrett's esophagus (BE) cases, and 16,354 controls. Logistic regression was used to estimate study-specific odds ratios (ORs) and 95% CIs for self-reported diabetes in association with EA, EGJA, and BE. Adjusted ORs were then combined using random-effects meta-analysis. RESULTS: Diabetes was associated with a 34% increased risk of EA (OR, 1.34; 95% CI, 1.00-1.80; I2  = 48.8% [where 0% indicates no heterogeneity, and larger values indicate increasing heterogeneity between studies]), 27% for EGJA (OR, 1.27; 95% CI, 1.05-1.55; I2  = 0.0%), and 30% for EA/EGJA combined (OR, 1.30; 95% CI, 1.06-1.58; I2  = 34.9%). Regurgitation symptoms modified the diabetes-EA/EGJA association (P for interaction = .04) with a 63% increased risk among participants with regurgitation (OR, 1.63; 95% CI, 1.19-2.22), but not among those without regurgitation (OR, 1.03; 95% CI, 0.74-1.43). No consistent association was found between diabetes and BE. CONCLUSIONS: Diabetes was associated with increased EA and EGJA risk, which was confined to individuals with regurgitation symptoms. Lack of an association between diabetes and BE suggests that diabetes may influence progression of BE to cancer.

Strengthening breast cancer services in Vietnam: a mixed-methods study.

BACKGROUND: Incidence of breast cancer has increased in Vietnam over the past two decades, but little data exists to inform policy and planning. This study examined the organisation and delivery of breast cancer services in Vietnam in order to address the lack of data on detection, diagnosis and treatment. METHODS: We gathered quantitative and qualitative data using an adapted survey-based Service Availability and Readiness Assessment (SARA) tool and semi-structured interviews from healthcare providers in 69 healthcare facilities about the experience and challenges of delivering breast cancer services. We conducted our study across four levels of the health system in three provinces in Vietnam. RESULTS: The analysis of our data show that a number of areas require strengthening particularly in relation to service availability and service readiness. Firstly, healthcare providers across all levels of the health system reported that service provision was constrained by a lack of resources both in relation to health infrastructure and training for healthcare providers. Secondly, access to timely diagnosis and treatment is limited due to services only being available at the top two levels of the health system. Women living outside the immediate vicinity of such facilities tend to find access more costly and time-consuming, and there is a need to investigate the social, economic, geographic and cultural barriers that may prevent women from accessing services. CONCLUSIONS: Our study suggests that there is a need to strengthen lower levels of the Vietnamese health system in relation to the detection of breast cancer. Provision of some services such as clinical breast examination, advice on self-examination, and conducting ultrasound tests (supported with appropriate training and capacity-building of healthcare providers) at commune and district levels of the health system may reduce the overcrowding and service-delivery burden experienced in provincial and national-level hospitals. Empowering lower levels of the health system to conduct breast cancer screening, which is currently undertaken on an ad hoc basis through higher-level facilities, is likely to improve access to services for women.

Pancreatic cancer and autoimmune diseases: An association sustained by computational and epidemiological case-control approaches.

Deciphering the underlying genetic basis behind pancreatic cancer (PC) and its associated multimorbidities will enhance our knowledge toward PC control. The study investigated the common genetic background of PC and different morbidities through a computational approach and further evaluated the less explored association between PC and autoimmune diseases (AIDs) through an epidemiological analysis. Gene-disease associations (GDAs) of 26 morbidities of interest and PC were obtained using the DisGeNET public discovery platform. The association between AIDs and PC pointed by the computational analysis was confirmed through multivariable logistic regression models in the PanGen European case-control study population of 1,705 PC cases and 1,084 controls. Fifteen morbidities shared at least one gene with PC in the DisGeNET database. Based on common genes, several AIDs were genetically associated with PC pointing to a potential link between them. An epidemiologic analysis confirmed that having any of the nine AIDs studied was significantly associated with a reduced risk of PC (Odds Ratio (OR) = 0.74, 95% confidence interval (CI) 0.58-0.93) which decreased in subjects having ≥2 AIDs (OR = 0.39, 95%CI 0.21-0.73). In independent analyses, polymyalgia rheumatica, and rheumatoid arthritis were significantly associated with low PC risk (OR = 0.40, 95%CI 0.19-0.89, and OR = 0.73, 95%CI 0.53-1.00, respectively). Several inflammatory-related morbidities shared a common genetic component with PC based on public databases. These molecular links could shed light into the molecular mechanisms underlying PC development and simultaneously generate novel hypotheses. In our study, we report sound findings pointing to an association between AIDs and a reduced risk of PC.

'Missed' oesophageal adenocarcinoma and high-grade dysplasia in Barrett's oesophagus patients: A large population-based study.

BACKGROUND: A systematic review suggests that 25% of oesophageal adenocarcinomas (OAC) are 'missed' at index endoscopy for Barrett's oesophagus (BO); however, this included few population-based studies and may be an overestimate. OBJECTIVE: The objective of this article is to quantify the 'missed' rates of high-grade dysplasia (HGD) and OAC at index BO endoscopy. METHODS: Patients from the Northern Ireland BO register diagnosed between 1993 and 2010 (n = 13,159) were linked to the Northern Ireland Cancer Registry to identify patients who developed OAC or HGD. Logistic regression analysis compared characteristics of 'missed' vs 'incident' HGD/OAC, defined as diagnoses within 3-12 months vs >1 year after incident BO, respectively. RESULTS: A total of 267 patients were diagnosed with HGD/OAC ≥3 months after BO diagnosis, of whom 34 (12.7%) were potentially 'missed'. The proportion of 'missed' HGD/OAC was 25% among BO patients with low-grade dysplasia (LGD) and 9% among non-dysplastic BO patients. Older age and BO-LGD carried a higher risk of 'missed' HGD/OAC. Non-dysplastic BO patients were more often diagnosed with a 'missed' OAC (rather than HGD; 89%), compared with BO-LGD patients (40%). CONCLUSIONS: Approximately one in 10 HGD/OAC cases are 'missed' at incident BO diagnosis, which is significant but lower than previous reports. However, 'missed' HGD/OAC cases represent only 0.26% of all BO patients.

Hormonal and reproductive factors and risk of upper gastrointestinal cancers in men: A prospective cohort study within the UK Biobank.

Incidence of upper gastrointestinal cancers of the oesophagus and stomach show a strong unexplained male predominance. Hormonal and reproductive factors have been associated with upper gastrointestinal cancers in women but there is little available data on men. To investigate this, we included 219,425 men enrolled in the UK Biobank in 2006-2010. Baseline assessments provided information on hormonal and reproductive factors (specifically hair baldness, number of children fathered, relative age at first facial hair and relative age voice broke) and incident oesophageal or gastric cancers were identified through linkage to U.K. cancer registries. Unadjusted and adjusted hazard ratios (HR) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models. During 8 years of follow-up, 309 oesophageal 210 gastric cancers occurred. There was some evidence that male pattern baldness, was associated with gastric cancer risk (adjusted HR 1.35, 95% CI 0.97, 1.88), particularly for frontal male pattern baldness (adjusted HR 1.52, 95% CI 1.02, 2.28). There was little evidence of association between other hormonal and reproductive factors and risk of oesophageal or gastric cancer, overall or by histological subtype. In the first study of a range of male hormonal and reproductive factors and gastric cancer, there was a suggestion that male pattern baldness, often used as a proxy of sex hormone levels, may be associated with gastric cancer. Future prospective studies that directly test circulating sex steroid hormone levels in relation to upper gastrointestinal cancer risk are warranted.

Low-dose aspirin use and survival in colorectal cancer: results from a population-based cohort study.

BACKGROUND: Aspirin has been proposed as a novel adjuvant agent in colorectal cancer (CRC). Six observational studies have reported CRC-specific survival outcomes in patients using aspirin after CRC diagnosis but the results from these studies have been conflicting. Using a population-based cohort design this study aimed to assess if low-dose aspirin use after diagnosis reduced CRC-specific mortality. METHODS: A cohort of 8391 patients with Dukes' A-C CRC (2009-2012) was identified from the Scottish Cancer Registry and linked to national prescribing and death records. Adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for CRC-specific mortality were calculated using time-dependent Cox regression. RESULTS: There were 1064 CRC-specific deaths after a median follow-up of 3.6 years. Post-diagnostic low-dose aspirin use was not associated with a reduction in CRC-specific mortality either before or after adjustment for confounders (adjusted HR = 1.17, 95% CI 1.00-1.36). In sensitivity analysis pre-diagnostic low-dose aspirin was also not associated with reduced CRC-specific mortality (adjusted HR = 0.96, 95% CI 0.88-1.05). CONCLUSION: Low-dose aspirin use, either before or after diagnosis, did not prolong survival in this population-based CRC cohort.

Breast cancer services in Vietnam: a scoping review.

BACKGROUND: Breast cancer incidence has been increasing consistently in Vietnam. Thus far, there have been no analytical reviews of research produced within this area. OBJECTIVES: We sought to analyse the nature andextent of empirical studies about breast cancer in Vietnam, identifying areas for future research and systemsstrengthening. METHODS: We undertook a scoping study using a five-stage framework to review published and grey literature in English and Vietnamese on breast cancer detection, diagnosis and treatment. We focused specifically on research discussing the health system and service provision. RESULTS: Our results show that breast cancer screening is limited, with no permanent or integrated national screening activities. There is a lack of information on screening processes and on the integration of screening services with other areas of the health system. Treatment is largely centralised, and across all services there is a lack of evaluation and data collection that would be informative for recommendations seeking to improve accessibility and quality of breast cancer services. CONCLUSIONS: This paper is the first scoping review of breast cancer services in Vietnam. It outlines areas for future focus for policy makers and researchers with the objective of strengthening service provision to women with breast cancer across the country while also providing a methodological example for how to conduct a collaborative scoping review.

Medications that relax the lower oesophageal sphincter and risk of oesophageal cancer: An analysis of two independent population-based databases.

Excessive lower oesophageal sphincter relaxation increases gastro-oesophageal acid reflux, an oesophageal adenocarcinoma risk factor. Medications that relax this sphincter (benzodiazepines, calcium channel blockers, nitrates, ß2 agonists and xanthines) could promote cancer. These medications were investigated in two independent datasets. In the Scottish Primary Care Clinical Informatics Unit (PCCIU) database, a nested case-control study of oesophageal cancer was performed using GP prescription records. Conditional logistic regression was used to calculate odds ratios (OR) and 95% confidence intervals (CIs) for medication use and oesophageal cancer. In UK Biobank, a cohort study was conducted using self-reported medication use. Cox regression was used to calculate hazard ratios (HRs) and 95% CIs for medication use and oesophageal cancer, and by tumour subtype. Overall, 1,979 oesophageal cancer patients were matched to 9,543 controls in PCCIU, and 355 of 475,768 participants developed oesophageal cancer in UK Biobank. None of the medications investigated were significantly associated with oesophageal cancer risk apart from ß2 agonists, which were associated with increased oesophageal cancer risk in PCCIU (adjusted OR 1.38, 95% CI 1.12, 1.70) but not in UK Biobank (adjusted HR 1.21, 95% CI 0.70, 2.08). Medications that relax the lower oesophageal sphincter were not associated with oesophageal cancer, apart from ß2 agonists. This increased cancer risk in ß2 agonist users merits further investigation.

Association between circulating levels of sex steroid hormones and esophageal adenocarcinoma in the FINBAR Study.

BACKGROUND: Esophageal adenocarcinoma (EA) is characterized by a strong male predominance. Sex steroid hormones have been hypothesized to underlie this sex disparity, but no population-based study to date has examined this potential association. METHODS: Using mass spectrometry and ELISA, we quantitated sex steroid hormones and sex hormone binding globulin, respectively, in plasma from males- 172 EA cases and 185 controls-within the Factors Influencing the Barrett/Adenocarcinoma Relationship (FINBAR) Study, a case-control investigation conducted in Northern Ireland and Ireland. Multivariable adjusted logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for associations between circulating hormones and EA. RESULTS: Higher androgen:estrogen ratio metrics were associated with increased odds of EA (e.g., testosterone:estradiol ratio ORQ4 v. Q1 = 2.58, 95%CI = 1.23-5.43; Ptrend = 0.009). All estrogens and androgens were associated with significant decreased odds of EA. When restricted to individuals with minimal to no decrease in body mass index, the size of association for the androgen:estrogen ratio was not greatly altered. CONCLUSIONS: This first study of sex steroid hormones and EA provides tentative evidence that androgen:estrogen balance may be a factor related to EA. Replication of these findings in prospective studies is needed to enhance confidence in the causality of this effect.

A combined connectivity mapping and pharmacoepidemiology approach to identify existing medications with breast cancer causing or preventing properties.

PURPOSE: We applied a novel combined connectivity mapping and pharmacoepidemiological approach to identify medications that alter breast cancer risk. METHODS: The connectivity mapping process identified 6 potentially cancer-causing (meloxicam, azithromycin, rizatriptan, citalopram, rosiglitazone, and verapamil) and 4 potentially cancer-preventing (bendroflumethiazide, sertraline, fluvastatin, and budesonide) medications that were suitable for pharmacoepidemiological investigation. Within the UK Clinical Practice Research Datalink, we matched 45,147 breast cancer cases to 45,147 controls based on age, year, and general practice. Medication use was determined from electronic prescribing records. We used conditional logistic regression to calculate odds ratios (ORs) for the association between medication use and cancer risk after adjustment for comorbidities, lifestyle factors, deprivation, and other medication use. RESULTS: Bendroflumethiazide was associated with increased breast cancer risk (OR: 1.11; 95% CI: 1.06, 1.15); however the connectivity mapping exercise predicted that this medication would reduce risk. There were no statistically significant associations for any of the other candidate medications, with ever use ORs ranging from 0.93 (95% CI: 0.78, 1.11) for azithromycin to 1.16 (95% CI: 0.99, 1.37) for verapamil. CONCLUSIONS: In this instance, our combined connectivity mapping and pharmacoepidemiological approach did not identify any additional medications that were substantially associated with breast cancer risk. This could be due to limitations in the connectivity mapping, such as implausible dosage requirements, or the pharmacoepidemiology, such as residual confounding.

Blood biomarkers for early diagnosis of oesophageal cancer: a systematic review.

BACKGROUND: Oesophageal cancer prognosis remains poor owing to the inability to detect the disease at an early stage. Nontissue (serum, urinary or salivary) biomarkers potentially offer less invasive methods to aid early detection of oesophageal cancer. We aimed to systematically review studies assessing the relationship between nontissue biomarkers and subsequent development of oesophageal cancer. METHODS: Using terms for biomarkers and oesophageal cancer, Medline, EMBASE and Web of Science were systematically searched for longitudinal studies, published until April 2016, which assessed the association between nontissue biomarkers and subsequent oesophageal cancer risk. Random effects meta-analyses were used to calculate pooled relative risk (RR) and 95% confidence intervals (CIs), where possible. RESULTS: A total of 39 studies were included. Lower serum pepsinogen I concentrations were associated with an increased risk of oesophageal squamous cell carcinoma (n=3 studies, pooled RR=2.20, 95% CI: 1.31-3.70). However, the association for the pepsinogen I : II ratio was not statistically significant (n=3 studies, pooled RR=2.22, 95% CI: 0.77-6.40), with a large degree of heterogeneity observed (I=68.0%). Higher serum glucose concentrations were associated with a modestly increased risk of total oesophageal cancer (n=3 studies, pooled RR=1.27, 95% CI: 1.02-1.57). No association was observed for total cholesterol and total oesophageal cancer risk (n=3 studies, pooled RR=0.95, 95% CI: 0.58-1.54). Very few studies have assessed other biomarkers for meta-analyses. CONCLUSION: Serum pepsinogen I concentrations could aid early detection of oesophageal squamous cell carcinoma. More prospective studies are needed to determine the use of other nontissue biomarkers in the early detection of oesophageal cancer.

Adenocarcinoma risk in gastric atrophy and intestinal metaplasia: a systematic review.

BACKGROUND: Gastric cancer (GC) has a poor prognosis with wide variation in survival rates across the world. Several studies have shown premalignant lesions gastric atrophy (GA) and intestinal metaplasia (IM) influence gastric cancer risk. This systematic review examines all available evidence of the risk of GC in patients with GA or IM and explores the geographical variation between countries. METHODS: EMBASE, MEDLINE, Web of Science and the Cochrane Library were searched for relevant articles published to June 2016 investigating the risk of GC in individuals with GA or IM. Analysis was performed to determine variation based on geographical location. Study quality was assessed using the Newcastle-Ottawa Scale and heterogeneity between studies was also evaluated. RESULTS: Fifteen relevant articles were identified, in which there were eight studies of GC incidence in GA and nine in IM cohorts (two articles investigated both GA and IM). The incidence rate of GC in patients with GA ranged from 0.53 to 15.24 per 1000 person years, whereas there was more variation in GC incidence in patients with IM (0.38 to 17.08 per 1000 person years). The greatest GC incidence rates were in Asian countries, for patients with GA, and the USA for those with IM (15.24 and 17.08 per 1000 person years, respectively). The largest studies (four over 25,000 person years) had an incidence rate range of 1.0-2.5 per 1000 person years, however, in general, study quality was poor and there was marked heterogeneity. CONCLUSION: Overall there is a wide variation in annual incidence rate of GC from premalignant lesions. With the recent introduction of surveillance guidelines for gastric atrophy and intestinal metaplasia in the Western world, future assessment of this risk should be performed. Furthermore, substantial heterogeneity supports the need for more robust studies in order to pool results and determine the overall incidence rate of gastric cancer for patients with these premalignant lesions.