Randomized Trial of Medical versus Surgical Treatment for Refractory Heartburn.

BACKGROUND: Heartburn that persists despite proton-pump inhibitor (PPI) treatment is a frequent clinical problem with multiple potential causes. Treatments for PPI-refractory heartburn are of unproven efficacy and focus on controlling gastroesophageal reflux with reflux-reducing medication (e.g., baclofen) or antireflux surgery or on dampening visceral hypersensitivity with neuromodulators (e.g., desipramine). METHODS: Patients who were referred to Veterans Affairs (VA) gastroenterology clinics for PPI-refractory heartburn received 20 mg of omeprazole twice daily for 2 weeks, and those with persistent heartburn underwent endoscopy, esophageal biopsy, esophageal manometry, and multichannel intraluminal impedance-pH monitoring. If patients were found to have reflux-related heartburn, we randomly assigned them to receive surgical treatment (laparoscopic Nissen fundoplication), active medical treatment (omeprazole plus baclofen, with desipramine added depending on symptoms), or control medical treatment (omeprazole plus placebo). The primary outcome was treatment success, defined as a decrease of 50% or more in the Gastroesophageal Reflux Disease (GERD)-Health Related Quality of Life score (range, 0 to 50, with higher scores indicating worse symptoms) at 1 year. RESULTS: A total of 366 patients (mean age, 48.5 years; 280 men) were enrolled. Prerandomization procedures excluded 288 patients: 42 had relief of their heartburn during the 2-week omeprazole trial, 70 did not complete trial procedures, 54 were excluded for other reasons, 23 had non-GERD esophageal disorders, and 99 had functional heartburn (not due to GERD or other histopathologic, motility, or structural abnormality). The remaining 78 patients underwent randomization. The incidence of treatment success with surgery (18 of 27 patients, 67%) was significantly superior to that with active medical treatment (7 of 25 patients, 28%; P = 0.007) or control medical treatment (3 of 26 patients, 12%; P<0.001). The difference in the incidence of treatment success between the active medical group and the control medical group was 16 percentage points (95% confidence interval, -5 to 38; P = 0.17). CONCLUSIONS: Among patients referred to VA gastroenterology clinics for PPI-refractory heartburn, systematic workup revealed truly PPI-refractory and reflux-related heartburn in a minority of patients. For that highly selected subgroup, surgery was superior to medical treatment. (Funded by the Department of Veterans Affairs Cooperative Studies Program; ClinicalTrials.gov number, NCT01265550.).

Subtypes of Barrett's oesophagus and oesophageal adenocarcinoma based on genome-wide methylation analysis.

OBJECTIVE: To identify and characterise DNA methylation subtypes in oesophageal adenocarcinoma (EAC) and its precursor Barrett's oesophagus (BE). DESIGN: We performed genome-wide DNA methylation profiling on samples of non-dysplastic BE from cancer-free patients (n=59), EAC (n=23), normal squamous oesophagus (n=33) and normal fundus (n=9), and identified methylation subtypes using a recursively partitioned mixture model. We assessed genomic alterations for 9 BE and 22 EAC samples with massively parallel sequencing of 243 EAC-associated genes, and we conducted integrative analyses with transcriptome data to identify epigenetically repressed genes. We also carried out in vitro experiments treating EAC cell lines with 5-Aza-2'-Deoxycytidine (5-Aza-dC), short hairpin RNA knockdown and anticancer therapies. RESULTS: We identified and validated four methylation subtypes of EAC and BE. The high methylator subtype (HM) of EAC had the greatest number of activating events in ERBB2 (p<0.05, Student's t-test) and the highest global mutation load (p<0.05, Fisher's exact test). PTPN13 was silenced by aberrant methylation in the HM subtype preferentially and in 57% of EACs overall. In EAC cell lines, 5-Aza-dC treatment restored PTPN13 expression and significantly decreased its promoter methylation in HM cell lines (p<0.05, Welch's t-test). Inhibition of PTPN13 expression in the SK-GT-4 EAC cell line promoted proliferation, colony formation and migration, and increased phosphorylation in ERBB2/EGFR/Src kinase pathways. Finally, EAC cell lines showed subtype-specific responses to topotecan, SN-38 and palbociclib treatment. CONCLUSIONS: We identified and characterised methylator subtypes in BE and EAC. We further demonstrated the biological and clinical relevance of EAC methylator subtypes, which may ultimately help guide clinical management of patients with EAC.

BVES regulates c-Myc stability via PP2A and suppresses colitis-induced tumourigenesis.

OBJECTIVE: Blood vessel epicardial substance (BVES) is a tight junction-associated protein that regulates epithelial-mesenchymal states and is underexpressed in epithelial malignancy. However, the functional impact of BVES loss on tumourigenesis is unknown. Here we define the in vivo role of BVES in colitis-associated cancer (CAC), its cellular function and its relevance to patients with IBD. DESIGN: We determined BVES promoter methylation status using an Infinium HumanMethylation450 array screen of patients with UC with and without CAC. We also measured BVES mRNA levels in a tissue microarray consisting of normal colons and CAC samples. Bves-/- and wild-type mice (controls) were administered azoxymethane (AOM) and dextran sodium sulfate (DSS) to induce tumour formation. Last, we used a yeast two-hybrid screen to identify BVES interactors and performed mechanistic studies in multiple cell lines to define how BVES reduces c-Myc levels. RESULTS: BVES mRNA was reduced in tumours from patients with CAC via promoter hypermethylation. Importantly, BVES promoter hypermethylation was concurrently present in distant non-malignant-appearing mucosa. As seen in human patients, Bves was underexpressed in experimental inflammatory carcinogenesis, and Bves-/- mice had increased tumour multiplicity and degree of dysplasia after AOM/DSS administration. Molecular analysis of Bves-/- tumours revealed Wnt activation and increased c-Myc levels. Mechanistically, we identified a new signalling pathway whereby BVES interacts with PR61α, a protein phosphatase 2A regulatory subunit, to mediate c-Myc destruction. CONCLUSION: Loss of BVES promotes inflammatory tumourigenesis through dysregulation of Wnt signalling and the oncogene c-Myc. BVES promoter methylation status may serve as a CAC biomarker.

Editorial: The Name Game: Circumventing Quality Metrics by Categorizing Incomplete Colonoscopy as Sigmoidoscopy.

Cecal intubation rate (CIR) is an important metric for colonoscopy quality. Guidelines propose a minimum CIR of 90% for all indications, and 95% in screening procedures. In this issue, a study of three UK teaching hospitals demonstrated one-third of endoscopists inappropriately converted colonoscopies to flexible sigmoidoscopies, and several endoscopists only reached the 90% CIR benchmark because of these inappropriate conversions. Our professional societies and healthcare organizations must continue to work to improve the accurate assessment of colonoscopy quality in order to identify underperforming clinicians who should be provided with additional training for the benefit of their patients.

A Molecular Clock Infers Heterogeneous Tissue Age Among Patients with Barrett's Esophagus.

Biomarkers that drift differentially with age between normal and premalignant tissues, such as Barrett's esophagus (BE), have the potential to improve the assessment of a patient's cancer risk by providing quantitative information about how long a patient has lived with the precursor (i.e., dwell time). In the case of BE, which is a metaplastic precursor to esophageal adenocarcinoma (EAC), such biomarkers would be particularly useful because EAC risk may change with BE dwell time and it is generally not known how long a patient has lived with BE when a patient is first diagnosed with this condition. In this study we first describe a statistical analysis of DNA methylation data (both cross-sectional and longitudinal) derived from tissue samples from 50 BE patients to identify and validate a set of 67 CpG dinucleotides in 51 CpG islands that undergo age-related methylomic drift. Next, we describe how this information can be used to estimate a patient's BE dwell time. We introduce a Bayesian model that incorporates longitudinal methylomic drift rates, patient age, and methylation data from individually paired BE and normal squamous tissue samples to estimate patient-specific BE onset times. Our application of the model to 30 sporadic BE patients' methylomic profiles first exposes a wide heterogeneity in patient-specific BE onset times. Furthermore, independent application of this method to a cohort of 22 familial BE (FBE) patients reveals significantly earlier mean BE onset times. Our analysis supports the conjecture that differential methylomic drift occurs in BE (relative to normal squamous tissue) and hence allows quantitative estimation of the time that a BE patient has lived with BE.

Comprehensive site-specific whole genome profiling of stromal and epithelial colonic gene signatures in human sigmoid colon and rectal tissue.

The strength of associations between various exposures (e.g., diet, tobacco, chemopreventive agents) and colorectal cancer risk may partially depend on the complex interaction between epithelium and stroma across anatomic subsites. Currently, baseline data describing genome-wide coding and long noncoding gene expression profiles in the healthy colon specific to tissue type and location are lacking. Therefore, colonic mucosal biopsies from 10 healthy participants who were enrolled in a clinical study to evaluate effects of lignan supplementation on gut resiliency were used to characterize the site-specific global gene expression signatures associated with stromal vs. epithelial cells in the sigmoid colon and rectum. Using RNA-seq, we demonstrate that tissue type and location patterns of gene expression and upstream regulatory pathways are distinct. For example, consistent with a key role of stroma in the crypt niche, mRNAs associated with immunoregulatory and inflammatory processes (i.e., CXCL14, ANTXR1), smooth muscle contraction (CALD1), proliferation and apoptosis (GLP2R, IGFBP3), and modulation of extracellular matrix (MMP2, COL3A1, MFAP4) were all highly expressed in the stroma. In comparison, HOX genes (HOXA3, HOXD9, HOXD10, HOXD11, and HOXD-AS2, a HOXD cluster antisense RNA 2), and WNT5B expression were also significantly higher in sigmoid colon compared with the rectum. These findings provide strong impetus for considering colorectal tissue subtypes and location in future observational studies and clinical trials designed to evaluate the effects of exposures on colonic health.

Epigenetic silencing of TPM2 contributes to colorectal cancer progression upon RhoA activation.

Beta-tropomyosin (ß-tropomyosin, TPM2) has been found to be downregulated in colorectal cancer (CRC) in previous studies. In this study, we aimed to investigate the mechanisms and potential biological consequences of the downregulation of TPM2 in colorectal cancer. TPM2 expression in colorectal cancer was assessed by qRT-PCR and immunostaining. The biological functions of TPM2 were assessed in cell lines either overexpressing or underexpressingTPM2. Aberrant DNA methylation in the promoter region is associated with suppression of TPM2 expression in primary colorectal cancer tissue samples. Treatment with the demethylation agent 5-AZA can induceTPM2 expression in colorectal cancer cell lines. Reconstitution of TPM2 suppresses cell proliferation and migration in colorectal cancer cell lines, whereas the loss of TPM2 expression is associated with increased tumor proliferation and migration in vitro, which was accompanied by RhoA activation. In summary, our findings indicate that TPM2 appears to be commonly silenced by aberrant DNA methylation in colon cancer. TPM2 loss is associated with RhoA activation and tumor proliferation.

Use of a novel polyp "ruler snare" improves estimation of colon polyp size.

BACKGROUND AND AIMS: Prior studies have demonstrated that endoscopists' estimates of polyp size are imprecise. The aim of this study was to determine whether a modified polypectomy "ruler snare" improves the accuracy of assessment of polyp size in real time without the use of additional devices. METHODS: Ten artificial polyps of predetermined sizes (4 to 25 mm) were affixed to the inside of a colon model. A standard polypectomy snare was modified by adding 5-mm graduated markings to the distal end of the plastic sheath. Study participants estimated the sizes of the artificial polyps during simulated colonoscopies, first using a standard snare and then with the modified ruler snare. RESULTS: Thirty-four private practice and academic gastroenterologists participated in the study. Endoscopists' ability to accurately classify polyps by size (diminutive, small, or large) improved from 48.5% to 60.3% with the ruler snare (P = .002). The greatest improvement in precision was seen among the large polyps, where accuracy increased from 35.9% to 58.2% with use of the ruler snare (P < .0001). Participants underestimated polyp size by a mean of 3.6 mm (interquartile range, -5 to -2 mm) with the standard snare and 1.8 mm (interquartile range, -3 to 0 mm) with the ruler snare, which corresponded to a 44.2% improvement in accuracy with the ruler snare (P < .05). CONCLUSIONS: The modified ruler snare improved polyp size assessment compared with a standard snare, particularly with large polyps. Overall, although size estimation continues to be imprecise, the addition of calibrated markings to a polypectomy snare is a simple and likely low-cost means to improve neoplasia surveillance recommendations.

Universal Screening of Colorectal Cancers for Lynch Syndrome: Challenges and Opportunities.

Lynch syndrome (LS) is the most common heritable colorectal cancer (CRC) syndrome, accounting for approximately 3 % of CRC cases in the USA each year. LS results from a genetic mutation in one of the four mismatch repair genes, and clinically LS is associated with CRC and other gastrointestinal and extra-gastrointestinal malignancies. In this review, we describe the various clinical criteria utilized for the identification of LS patients and the inherent flaws with these criteria. We discuss the concept of universal testing for LS in all cases of newly diagnosed CRC, along with the potential benefits and challenges of universal testing. Several studies have shown that universal tumor testing is cost-effective and identifies cases of LS that are missed using traditional clinical criteria, which may result in reduced cancer mortality for probands and their families. Yet the full benefits of universal tumor testing may be limited by the availability and patient acceptance of genetic testing, and by logistical obstacles affecting the implementation of universal testing programs. Lastly, we comment on developing technologies such as massively parallel next-generation sequencing, which permits simultaneous sequencing of multiple genes involved in LS and other inherited colon cancer syndromes.

NTRK3 is a potential tumor suppressor gene commonly inactivated by epigenetic mechanisms in colorectal cancer.

NTRK3 is a member of the neurotrophin receptor family and regulates cell survival. It appears to be a dependence receptor, and thus has the potential to act as an oncogene or as a tumor suppressor gene. NTRK3 is a receptor for NT-3 and when bound to NT-3 it induces cell survival, but when NT-3 free, it induces apoptosis. We identified aberrantly methylated NTRK3 in colorectal cancers through a genome-wide screen for hypermethylated genes. This discovery led us to assess whether NTRK3 could be a tumor suppressor gene in the colon. NTRK3 is methylated in 60% of colon adenomas and 67% of colon adenocarcinomas. NTRK3 methylation suppresses NTRK3 expression. Reconstitution of NTRK3 induces apoptosis in colorectal cancers, if NT-3 is absent. Furthermore, the loss of NTRK3 expression associates with neoplastic transformation in vitro and in vivo. We also found that a naturally occurring mutant NTRK3 found in human colorectal cancer inhibits the tumor suppressor activity of NTRK3. In summary, our findings suggest NTRK3 is a conditional tumor suppressor gene that is commonly inactivated in colorectal cancer by both epigenetic and genetic mechanisms whose function in the pathogenesis of colorectal cancer depends on the expression status of its ligand, NT-3.

Differences in DNA methylation signatures reveal multiple pathways of progression from adenoma to colorectal cancer.

BACKGROUND & AIMS: Genetic and epigenetic alterations contribute to the pathogenesis of colorectal cancer (CRC). There is considerable molecular heterogeneity among colorectal tumors, which appears to arise as polyps progress to cancer. This heterogeneity results in different pathways to tumorigenesis. Although epigenetic and genetic alterations have been detected in conventional tubular adenomas, little is known about how these affect progression to CRC. We compared methylomes of normal colon mucosa, tubular adenomas, and colorectal cancers to determine how epigenetic alterations might contribute to cancer formation. METHODS: We conducted genome-wide array-based studies and comprehensive data analyses of aberrantly methylated loci in 41 normal colon tissue, 42 colon adenomas, and 64 cancers using HumanMethylation450 arrays. RESULTS: We found genome-wide alterations in DNA methylation in the nontumor colon mucosa and cancers. Three classes of cancers and 2 classes of adenomas were identified based on their DNA methylation patterns. The adenomas separated into classes of high-frequency methylation and low-frequency methylation. Within the high-frequency methylation adenoma class a subset of adenomas had mutant KRAS. Additionally, the high-frequency methylation adenoma class had DNA methylation signatures similar to those of cancers with low or intermediate levels of methylation, and the low-frequency methylation adenoma class had methylation signatures similar to that of nontumor colon tissue. The CpG sites that were differentially methylated in these signatures are located in intragenic and intergenic regions. CONCLUSIONS: Genome-wide alterations in DNA methylation occur during early stages of progression of tubular adenomas to cancer. These findings reveal heterogeneity in the pathogenesis of colorectal cancer, even at the adenoma step of the process.

Aberrantly methylated PKP1 in the progression of Barrett's esophagus to esophageal adenocarcinoma.

The aberrant DNA methylation of tumor suppressor genes occurs frequently in Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC) and likely affects the initiation and progression of BE to EAC. In the present study, we discovered PKP1 as a novel methylated gene in EAC and then investigated the role of loss of PKP1, a constituent of the desmosome complex found in stratified epithelial layers, on the behavior of Barrett's esophagus and esophageal adenocarcinoma cells. By using primary esophageal tissue samples we determined that PKP1 was rarely methylated in normal squamous esophagus (5/55; 9.1%) and BE (5/39; 12.8%) and more frequently methylated in Barrett's esophagus with high-grade dysplasia (HGD) or EAC (20/60; 33.3%; P < 0.05). Furthermore, PKP1 levels were decreased in BE and HGD/EAC cases compared to normal squamous esophagus cases. Knockdown of PKP1 in the BE cell lines CP-A and CP-D (both normally express PKP1) resulted in increased cell motility. Thus, PKP1 loss secondary to promoter methylation, as well as other mechanisms, may promote the progression of BE to EAC in a subset of patients via decreased desmosome assembly and increased cell motility.

Chemoprevention of esophageal adenocarcinoma.

Esophageal adenocarcinoma (EAC) is a major cause of cancer-related death, particularly in Western populations, and is rapidly rising in Asian populations at this time. Virtually all EACs develop from the precursor lesion Barrett's esophagus (BE), which is the most significant risk factor for EAC. However, the rates of progression from BE to EAC are low and patients with BE are asymptomatic. Thus, any strategy for EAC prevention must carry a low risk of harm in order to be clinically useful. Since current EAC-screening and BE-surveillance methods carry some procedural risk and are burdensome, there is an opportunity for chemoprevention, i.e. medications or dietary factors that may prevent BE from progressing to EAC. A variety of candidate chemoprevention therapies have been assessed to date. Proton-pump inhibitors (PPIs) are the best studied and have modest EAC-chemoprevention efficacy in BE patients, with a recent randomized trial showing that high-dose PPI may be more effective than low-dose PPI. Aspirin and other non-steroidal anti-inflammatory drugs have moderate quality observational and randomized-trial evidence for preventing progression of BE to EAC, but their risks for harm have precluded their routine clinical use. Other therapies (statins, metformin, female sex hormones) generally do not have strong evidence to support their use in EAC chemoprevention. Although progress has been made in this field, there is still a need for more effective and safe chemoprevention therapies for EAC.

Epigenetic Inactivation of α-Internexin Accelerates Microtubule Polymerization in Colorectal Cancer.

DNA methylation contributes to malignant transformation, but little is known about how the methylation drives colorectal cancer evolution at the early stages. Here we identify aberrant INA (α-internexin) gene methylation in colon adenoma and adenocarcinoma by filtering data obtained from a genome-wide screen of methylated genes. The gene encoding INA, a type IV intermediate filament, was frequently hypermethylated in CpG islands located in the promoter region. This hypermethylation preferentially occurred in large tumors and was a prognostic marker for poor overall survival in patients with colorectal cancer. This type of epigenetic alteration silenced INA expression in both adenoma and adenocarcinoma tissues. Gene silencing of INA in colorectal cancer cells increased cell proliferation, migration, and invasion. Restored INA expression blocked migration and invasion in vitro and reduced lung metastasis in vivo. Mechanistically, INA directly inhibited microtubule polymerization in vitro and decreased intracellular microtubule plus-end assembly rates. A peptide array screen surveying the tubulin-binding sites in INA identified a tubulin-binding motif located in the N-terminal head domain that plays a tumor-suppressive role by binding to unpolymerized tubulins and impeding microtubule polymerization. Thus, epigenetic inactivation of INA is an intermediate filament reorganization event that is essential to accelerate microtubule polymerization in the early stages of colorectal cancer. SIGNIFICANCE: This work provides insight into the epigenetic inactivation of INA, a novel identified tumor suppressor, which increases microtubule polymerization during colorectal cancer progression.

Colonic mucosal and exfoliome transcriptomic profiling and fecal microbiome response to a flaxseed lignan extract intervention in humans.

BACKGROUND: Microbial metabolism of lignans from high-fiber plant foods produces bioactive enterolignans, such as enterolactone (ENL) and enterodiol (END). Enterolignan exposure influences cellular pathways important to cancer risk and is associated with reduced colon tumorigenesis in animal models and lower colorectal cancer risk in humans. OBJECTIVES: The aim of this study was to test the effects of a flaxseed lignan supplement (50 mg secoisolariciresinol diglucoside/d) compared with placebo on host gene expression in colon biopsies and exfoliated colonocyte RNA in feces and fecal microbial community composition, and to compare responses in relation to ENL excretion. METHODS: We conducted a 2-period randomized, crossover intervention in 42 healthy men and women (20-45 y). We used RNA-seq to measure differentially expressed (DE) genes in colonic mucosa and fecal exfoliated cells through the use of edgeR and functional analysis with Ingenuity Pathway Analysis. We used 16S ribosomal RNA gene (V1-V3) analysis to characterize the fecal microbiome, and measured END and ENL in 24-h urine samples by gas chromatography-mass spectrometry. RESULTS: We detected 32 DE genes (false discovery rate <0.05) in the exfoliome, but none in the mucosal biopsies, in response to 60 d of lignan supplement compared with placebo. Statistically significant associations were detected between ENL excretion and fecal microbiome measured at baseline and at the end of the intervention periods. Further, we detected DE genes in colonic mucosa and exfoliome between low- and high-ENL excreters. Analysis of biopsy samples indicated that several anti-inflammatory upstream regulators, including transforming growth factor ß and interleukin 10 receptor, were suppressed in low-ENL excreters. Complementary analyses in exfoliated cells also suggested that low-ENL excreters may be predisposed to proinflammatory cellular events due to upregulation of nuclear transcription factor κB and NOS2, and an inhibition of the peroxisome proliferator-activated receptor γ network. CONCLUSIONS: These results suggest that ENL or other activities of the associated gut microbial consortia may modulate response to a dietary lignan intervention. This has important implications for dietary recommendations and chemoprevention strategies. This study was registered at clinicaltrials.gov as NCT01619020.

Implications of Epigenetic Drift in Colorectal Neoplasia.

Many normal tissues undergo age-related drift in DNA methylation, providing a quantitative measure of tissue age. Here, we identify and validate 781 CpG islands (CGI) that undergo significant methylomic drift in 232 normal colorectal tissues and show that these CGI continue to drift in neoplasia while retaining significant correlations across samples. However, compared with normal colon, this drift advanced (∼3-4-fold) faster in neoplasia, consistent with increased cell proliferation during neoplastic progression. The observed drift patterns were broadly consistent with modeled adenoma-to-carcinoma sojourn time distributions from colorectal cancer incidence data. These results support the hypothesis that, beginning with the founder premalignant cell, cancer precursors frequently sojourn for decades before turning into cancer, implying that the founder cell typically arises early in life. At least 77% to 89% of the observed drift variance in distal and rectal tumors was explained by stochastic variability associated with neoplastic progression, whereas only 55% of the variance was explained for proximal tumors. However, gene-CGI pairs in the proximal colon that underwent drift were significantly and primarily negatively correlated with cancer gene expression, suggesting that methylomic drift participates in the clonal evolution of colorectal cancer. Methylomic drift advanced in colorectal neoplasia, consistent with extended sojourn time distributions, which accounts for a significant fraction of epigenetic heterogeneity in colorectal cancer. Importantly, these estimated long-duration premalignant sojourn times suggest that early dietary and lifestyle interventions may be more effective than later changes in reducing colorectal cancer incidence. SIGNIFICANCE: These findings present age-related methylomic drift in colorectal neoplasia as evidence that premalignant cells can persist for decades before becoming cancerous.See related commentary by Sapienza, p. 437.

Oxygen regulation of tumor perfusion by S-nitrosohemoglobin reveals a pressor activity of nitric oxide.

In erythrocytes, S-nitrosohemoglobin (SNO-Hb) arises from S-nitrosylation of oxygenated hemoglobin (Hb). It has been shown that SNO-Hb behaves as a nitric oxide (NO) donor at low oxygen tensions. This property, in combination with oxygen transport capacity, suggests that SNO-Hb may have unique potential to reoxygenate hypoxic tissues. The present study was designed to test the idea that the allosteric properties of SNO-Hb could be manipulated to enhance oxygen delivery in a hypoxic tumor. Using Laser Doppler flowmetry, we showed that SNO-Hb infusion to animals breathing 21% O2 reduced tumor perfusion without affecting blood pressure and heart rate. Raising the pO2 (100% O2) slowed the release of NO bioactivity from SNO-Hb (ie, prolonged the plasma half-life of the SNO in Hb), preserved tumor perfusion, and raised the blood pressure. In contrast, native Hb reduced both tumor perfusion and heart rate independently of the oxygen concentration of the inhaled gas, and did not elicit hypertensive effects. Window chamber (to image tumor arteriolar reactivity in vivo) and hemodynamic measurements indicated that the preservation of tissue perfusion by micromolar concentrations of SNO-Hb is a composite effect created by reduced peripheral vascular resistance and direct inhibition of the baroreceptor reflex, leading to increased blood pressure. Overall, these results indicate that the properties of SNO-Hb are attributable to allosteric control of NO release by oxygen in central as well as peripheral issues.

Anal intraepithelial neoplasia: A review of diagnosis and management.

Anal intraepithelial neoplasia (AIN) is a premalignant lesion of the anal mucosa that is a precursor to anal cancer. Although anal cancer is relatively uncommon, rates of this malignancy are steadily rising in the United States, and among certain high risk populations the incidence of anal cancer may exceed that of colon cancer. Risk factors for AIN and anal cancer consist of clinical factors and behaviors that are associated with the acquisition and persistence of human papilloma virus (HPV) infection. The strongest HPV-associated risk factors are HIV infection, receptive anal intercourse, and high risk sexual behavior. A history of HPV-mediated genital cancer, which suggests infection with an oncogenic HPV strain, is another risk factor for AIN/anal cancer. Because progression of AIN to anal cancer is known to occur in some individuals over several years, screening for AIN and early anal cancer, as well as treatment of advanced AIN lesions, is reasonable in certain high-risk populations. Although randomized controlled trials evaluating screening and treatment outcomes are lacking, experts support routine screening for AIN in high risk populations. Screening is performed using anal cytological exams, similar to those performed in cervical cancer screening programs, along with direct tissue evaluation and biopsy via high resolution anoscopy. AIN can be treated using topical therapies such as imiquimod, 5-flurouracil, and trichloroacetic acid, as well as ablative therapies such as electrocautery and laser therapy. Reductions in AIN and anal cancer rates have been shown in studies where high-risk populations were vaccinated against the oncogenic strains of HPV. Currently, the CDC recommends both high-risk and average-risk populations be vaccinated against HPV infection using the quadrivalent or nonavalent vaccines. It is important for clinicians to be familiar with AIN and the role of HPV vaccination, particularly in high risk populations.

Erratum to: Global DNA methylation patterns in Barrett's esophagus, dysplastic Barrett's, and esophageal adenocarcinoma are associated with BMI, gender, and tobacco use.

[This corrects the article DOI: 10.1186/s13148-016-0273-7.].