Stool DNA testing for the detection of colorectal neoplasia in patients with inflammatory bowel disease

Effects of DNA methylation and its application in inflammatory bowel disease (Review)

Inflammatory bowel disease (IBD) is marked by persistent inflammation, and its development and progression are linked to environmental, genetic, immune system and gut microbial factors. DNA methylation (DNAm), as one of the protein modifications, is a crucial epigenetic process used by cells to control gene transcription. DNAm is one of the most common areas that has drawn increasing attention recently, with studies revealing that the interleukin (IL)‑23/IL‑12, wingless‑related integration site, IL‑6‑associated signal transducer and activator of transcription 3, suppressor of cytokine signaling 3 and apoptosis signaling pathways are involved in DNAm and in the pathogenesis of IBD. It has emerged that DNAm‑associated genes are involved in perpetuating the persistent inflammation that characterizes a number of diseases, including IBD, providing a novel therapeutic strategy for exploring their treatment. The present review discusses DNAm‑associated genes in the pathogenesis of IBD and summarizes their application as possible diagnostic, prognostic and therapeutic biomarkers in IBD. This may provide a reference for the particular form of IBD and its related methylation genes, aiding in clinical decision‑making and encouraging therapeutic alternatives.

Pathology and Clinical Significance of Inflammatory Bowel Disease-Associated Colorectal Dysplastic Lesions

Timely diagnosis and effective management of colorectal dysplasia play a vital role in preventing mortality from colorectal cancer in patients with chronic inflammatory bowel disease. This review provides a contemporary overview of the pathologic and endoscopic classification of dysplasia in inflammatory bowel disease, their roles in determining surveillance and management algorithms, and emerging diagnostic and therapeutic approaches that might further enhance patient management.

Current Research on Molecular Biomarkers for Colorectal Cancer in Stool Samples

Colorectal cancer (CRC) is one of the most diagnosed cancers worldwide, with a high incidence and mortality rate when diagnosed late. Currently, the methods used in healthcare to diagnose CRC are the fecal occult blood test, flexible sigmoidoscopy, and colonoscopy. However, the lack of sensitivity and specificity and low population adherence are driving the need to implement other technologies that can identify biomarkers that not only help with early CRC detection but allow for the selection of more personalized treatment options. In this regard, the implementation of omics technologies, which can screen large pools of biological molecules, coupled with molecular validation, stands out as a promising tool for the discovery of new biomarkers from biopsied tissues or body fluids. This review delves into the current state of the art in the identification of novel CRC biomarkers that can distinguish cancerous tissue, specifically from fecal samples, as this could be the least invasive approach.

Assessment of Stool DNA Markers to Detect Colorectal Neoplasia in Patients with Inflammatory Bowel Disease: A Multi-site Case-control Study

BACKGROUND AND AIMS

The FDA-approved multitarget stool-DNA [mt-sDNA] test is a successful colorectal cancer [CRC] screening tool in average-risk individuals but is not indicated for patients with inflammatory bowel disease [IBD]. We determined the performance of the mt-sDNA assay without the haemoglobin component [mt-sDNAHgb-] in patients with IBD, while measuring sensitivity for colorectal cancer and advanced colorectal neoplasia [ACRN].

METHODS

This was a multi-centre, proof-of-concept investigation in persons aged 18-84 years with a diagnosis of IBD, or primary sclerosing cholangitis [PSC] with IBD. Enrolment occurred between March 2013 and May 2016. Stool was tested with the mt-sDNA molecular markers only, minus the immunochemical haemoglobin component.

RESULTS

The analysis set contained 355 samples. The median age was 52 [range 39-62] years, 45.6% were female and 93% were White. Two-thirds [63%] had ulcerative colitis [UC] and 10.1% had PSC/IBD. Colonoscopy revealed cancer in 8.5% [N = 30], advanced precancerous lesions [APLs] in 9.3% [N = 33] and non-advanced precancerous lesions in 7.6% [N = 27], and three-quarters [74.7%, N = 265] had negative findings. mt-sDNAHgb- sensitivity was 73.3% for any stage cancers, and 76.2% for ACRN. Sensitivity was highest for IBD-associated high-grade dysplasia at 100% and 84.6% for IBD-associated low-grade dysplasia ≥1 cm. The test showed higher sensitivity and lower specificity in UC than in Crohn's disease. Increasing inflammation score was associated with a significant decrease in mt-sDNAHgb- test score [ = 0.028] amongst neoplasia-negative individuals, but not in patients with ACRN.

CONCLUSIONS

These data highlight the potential of multitarget stool-DNA marker testing as an important addition to colorectal cancer surveillance by complementing colonoscopic evaluations in IBD patients.

Elevated EVL Methylation Level in the Normal Colon Mucosa Is a Potential Risk Biomarker for Developing Recurrent Adenomas

BACKGROUND

Individuals with adenomatous colorectal polyps undergo repeated colonoscopy surveillance to identify and remove metachronous adenomas. However, many patients with adenomas do not develop recurrent adenomas. Better methods to evaluate who benefits from increased surveillance are needed. We evaluated the use of altered EVL methylation as a potential biomarker for risk of recurrent adenomas.

METHODS

Patients with ≥1 colonoscopy had EVL methylation (mEVL) measured with an ultra-accurate methylation-specific droplet digital PCR assay on normal colon mucosa. The association between EVL methylation levels and adenoma or colorectal cancer was evaluated using three case/control definitions in three models: unadjusted (model 1), adjusting for baseline characteristics (model 2), and an adjusted model excluding patients with colorectal cancer at baseline (model 3).

RESULTS

Between 2001 and 2020, 136 patients were included; 74 healthy patients and 62 patients with a history of colorectal cancer. Older age, never smoking, and baseline colorectal cancer were associated with higher levels of mEVL (P ≤ 0.05). Each log base 10 difference in mEVL was associated with an increased risk of adenoma(s) or cancer at/after baseline for model 1 [OR, 2.64; 95% confidence interval (CI), 1.09-6.36], and adenoma(s) or cancer after baseline for models 1 (OR, 2.01; 95% CI, 1.04-3.90) and model 2 (OR, 3.17; 95% CI, 1.30-7.72).

CONCLUSIONS

Our results suggest that EVL methylation level detected in the normal colon mucosa has the potential to be a biomarker for monitoring the risk for recurrent adenomas.

IMPACT

These findings support the potential utility of EVL methylation for improving the accuracy for assigning risk for recurrent colorectal adenomas and cancer.

Colorectal cancer screening: The role of MT-sDNA testing

ABSTRACT

Because an estimated 10.5% of new colorectal cancer (CRC) cases occur in patients under age 50 years, the US Preventive Services Task Force in 2021 recommended CRC screening for adults ages 45 to 49 years. The prevalence of up-to-date CRC screening with any recommended test among patients age 45 years and older in the United States is only 59% in 2023, indicating that existing screening practices are ineffective. Screening options now include invasive and noninvasive measures. Multi-target stool DNA (MT-sDNA) testing is a simple, low-risk, noninvasive test that provides excellent sensitivity and specificity, is cost-effective, and may increase patient screening rates. CRC screening guideline recommendations and alternative screening methods may help improve patient outcomes and reduce morbidity and mortality. This article describes MT-sDNA testing, its effectiveness, recommended use, and potential expanding role as a screening option.

Recent developments on BMPs and their antagonists in inflammatory bowel diseases

Inflammatory bowel diseases (IBDs), including ulcerative colitis, and Crohn's disease, are intestinal disorders characterized by chronic relapsing inflammation. A large proportion of patients with IBD will progress to develop colitis-associated colorectal cancer due to the chronic intestinal inflammation. Biologic agents that target tumour necrosis factor-α, integrin α4β7, and interleukin (IL)12/23p40 have been more successful than conventional therapies in treating IBD. However, drug intolerance and loss of response are serious drawbacks of current biologics, necessitating the development of novel drugs that target specific pathways in IBD pathogenesis. One promising group of candidate molecules are bone morphogenetic proteins (BMPs), members of the TGF-β family involved in regulating morphogenesis, homeostasis, stemness, and inflammatory responses in the gastrointestinal tract. Also worth examining are BMP antagonists, major regulators of these proteins. Evidence has shown that BMPs (especially BMP4/6/7) and BMP antagonists (especially Gremlin1 and follistatin-like protein 1) play essential roles in IBD pathogenesis. In this review, we provide an updated overview on the involvement of BMPs and BMP antagonists in IBD pathogenesis and in regulating the fate of intestinal stem cells. We also described the expression patterns of BMPs and BMP antagonists along the intestinal crypt-villus axis. Lastly, we synthesized available research on negative regulators of BMP signalling. This review summarizes recent developments on BMPs and BMP antagonists in IBD pathogenesis, which provides novel insights into future therapeutic strategies.

Optimising inflammatory bowel disease surveillance and dysplasia management-Where do we stand?

Patients with longstanding extensive colitis are at an increased risk of developing colorectal cancer (CRC), and are therefore enrolled into colonoscopy screening programmes with the aim of detecting pre-cancerous dysplastic change. However, current surveillance programs face multiple limitations relating to low levels of patient enrolment, missed lesions resulting in interval cancers, and uncertainties in the management of dysplasia. Patient counselling regarding the endoscopic and surgical management options of dysplastic lesions can prove particularly challenging, due to the variable risk of progression to cancer. In this review, we discuss the histopathological diagnosis of inflammatory bowel disease (IBD)-associated dysplasia, describe the techniques to maximise dysplasia detection, and present a standardised multi-disciplinary approach to managing patients with dysplasia. The challenges presented by this patient cohort highlight the clear clinical need for further research into the development and validation of non-invasive markers of CRC risk in IBD patients undergoing surveillance.

Novel Diagnostic Biomarkers in Colorectal Cancer

Colorectal cancer (CRC) is still a leading cause of cancer death worldwide. Less than half of cases are diagnosed when the cancer is locally advanced. CRC is a heterogenous disease associated with a number of genetic or somatic mutations. Diagnostic markers are used for risk stratification and early detection, which might prolong overall survival. Nowadays, the widespread use of semi-invasive endoscopic methods and feacal blood tests characterised by suboptimal accuracy of diagnostic results has led to the detection of cases at later stages. New molecular noninvasive tests based on the detection of CRC alterations seem to be more sensitive and specific then the current methods. Therefore, research aiming at identifying molecular markers, such as DNA, RNA and proteins, would improve survival rates and contribute to the development of personalized medicine. The identification of “ideal” diagnostic biomarkers, having high sensitivity and specificity, being safe, cheap and easy to measure, remains a challenge. The purpose of this review is to discuss recent advances in novel diagnostic biomarkers for tumor tissue, blood and stool samples in CRC patients.

Value of methylation markers in colorectal cancer (Review)

Colorectal cancer (CRC) is a multifactorial and multistage process that occurs due to both genetic and epigenetic variations in normal epithelial cells. Analysis of the CRC epigenome has revealed that almost all CRC types have a large number of abnormally methylated genes. Hypermethylation of cell‑free DNA from CRC in the blood or stool is considered as a potential non‑invasive cancer biomarker, and various methylation markers have shown high sensitivity and specificity. The aim of the present review was to examine potential methylation markers in CRC that have been used or are expected to be used in the clinical setting, focusing on their screening, predictive, prognostic and therapeutic roles in CRC.

Predicting Colorectal Cancer Occurrence in IBD

Patients with colonic inflammatory bowel disease (IBD) are at an increased risk of developing colorectal cancer (CRC), and are therefore enrolled into a surveillance programme aimed at detecting dysplasia or early cancer. Current surveillance programmes are guided by clinical, endoscopic or histological predictors of colitis-associated CRC (CA-CRC). We have seen great progress in our understanding of these predictors of disease progression, and advances in endoscopic technique and management, along with improved medical care, has been mirrored by the falling incidence of CA-CRC over the last 50 years. However, more could be done to improve our molecular understanding of CA-CRC progression and enable better risk stratification for patients with IBD. This review summarises the known risk factors associated with CA-CRC and explores the molecular landscape that has the potential to complement and optimise the existing IBD surveillance programme.

Performance evaluation of stool DNA methylation tests in colorectal cancer screening: a systematic review and meta-analysis

AIM

There is not sufficient evidence about whether stool DNA methylation tests allow prioritizing patients to colonoscopy. Due to the COVID-19 pandemic, there will be a wait-list for rescheduling colonoscopies once the mitigation is lifted. The aim of this meta-analysis was to evaluate the accuracy of stool DNA methylation tests in detecting colorectal cancer.

METHODS

The PubMed, Cochrane Library and MEDLINE via Ovid were searched. Studies reporting the accuracy (Sackett phase 2 or 3) of stool DNA methylation tests to detect sporadic colorectal cancer were included. The DerSimonian-Laird method with random-effects model was utilized for meta-analysis.

RESULTS

Forty-six studies totaling 16 149 patients were included in the meta-analysis. The pooled sensitivity and specificity of all single genes and combinations was 62.7% (57.7%, 67.4%) and 91% (89.5%, 92.2%), respectively. Combinations of genes provided higher sensitivity compared to single genes (80.8% [75.1%, 85.4%] vs. 57.8% [52.3%, 63.1%]) with no significant decrease in specificity (87.8% [84.1%, 90.7%] vs. 92.1% [90.4%, 93.5%]). The most accurate single gene was found to be SDC2 with a sensitivity of 83.1% (72.6%, 90.2%) and a specificity of 91.2% (88.6%, 93.2%).

CONCLUSIONS

Stool DNA methylation tests have high specificity (92%) with relatively lower sensitivity (81%). Combining genes increases sensitivity compared to single gene tests. The single most accurate gene is SDC2, which should be considered for further research.

Genomic and epigenomic biomarkers in colorectal cancer: From diagnosis to therapy

Colorectal cancer (CRC) is the second leading cause of cancer-related deaths in the United States. Despite ongoing efforts aimed at increasing screening for CRC and early detection, and development of more effective therapeutic regimens, the overall morbidity and mortality from this malignancy remains a clinical challenge. Therefore, identifying and developing genomic and epigenomic biomarkers that can improve CRC diagnosis and help predict response to current therapies are of paramount importance for improving survival outcomes in CRC patients, sparing patients from toxicity associated with current regimens, and reducing the economic burden associated with these treatments. Although efforts to develop biomarkers over the past decades have achieved some success, the recent availability of high-throughput analytical tools, together with the use of machine learning algorithms, will likely hasten the development of more robust diagnostic biomarkers and improved guidance for clinical decision-making in the coming years. In this chapter, we provide a systematic and comprehensive overview on the current status of genomic and epigenomic biomarkers in CRC, and comment on their potential clinical significance in the management of patients with this fatal malignancy, including in the context of precision medicine.

Patients' perception of colonoscopy and acceptance of colonoscopy based IBD related colorectal cancer surveillance

OBJECTIVES

Patients with Inflammatory Bowel Disease (IBD) are at an increased risk of colorectal cancer (CRC). Current surveillance for CRC involves often uncomfortable colonoscopy. To assess IBD patients' perception of colonoscopy and examine preferences for hypothetical alternatives.

METHODS

IBD patients in clinical remission rated acceptable frequency of colonoscopy and hypothetical alternatives to colonoscopy-based surveillance (preference of yearly blood, yearly stool or 5-yearly imaging tests over 5-yearly colonoscopy). Participants rated discomfort of the last colonoscopy was compared with hospital records.

RESULTS

Of 282 patients with recollection of colonoscopy 65.8% rated the discomfort as moderate to severe, which correlated weakly with endoscopists' perception (r = 0.225; p = 0.015). There were no significant differences in patients' or endoscopists' perceptions of discomfort between sedated and unsedated colonoscopies. Undergoing a yearly colonoscopy was acceptable to 49.5%. Experienced discomfort did not correlate with patients' views on acceptable frequency of surveillance colonoscopy. Over 95% of patients would prefer blood, stool, or imaging tests over colonoscopy but nearly half expected sensitivities ≥95%.

CONCLUSION

A large proportion of IBD patients experienced colonoscopy as moderate to severely uncomfortable but would still accept colonoscopy surveillance frequency according to current guidance. Participants expected sensitivities ≥95% for potential alternatives to colonoscopy-based surveillance programs.

EXPERT OPINION

IBD patients frequently experience colonoscopy as uncomfortable but accept colonoscopy as the gold standard for colorectal cancer surveillance. The currently suggested frequencies of surveillance by colonoscopy are acceptable to IBD patients. They do however express a clear preference for non-invasive surveillance techniques. Some promising initial results have been obtained based on faecal or blood sampling. However, these have yet to be tested in large prospective studies to determine their sensitivity and specificity. IBD patients expect these non-invasive tests to meet high standards for sensitivity. In our view it is feasible that analogue to faecal immunochemistry based testing for general population bowel cancer screening non-invasive IBD surveillance techniques will emerge. This could lead to a reduction in the need for colonoscopy to those testing positive on faecal or blood based surveillance.

A loss-of-function mutation p.T256M in NDRG4 is implicated in the pathogenesis of pulmonary atresia with ventricular septal defect (PA/VSD) and tetralogy of Fallot (TOF)

Pulmonary atresia with ventricular septal defect (PA/VSD) is a rare congenital heart disease (CHD) characterized by a lack of luminal continuity and blood flow from either the right ventricle or the pulmonary artery, together with VSDs. The prevalence of PA/VSD is about 0.2% of live births and approximately 2% of CHDs. PA/VSD is similar to tetralogy of Fallot (TOF) in terms of structural and pathological characteristics. The pathogenesis of these two CHDs remains incompletely understood. It was previously reported that N‐myc downstream‐regulated gene (NDRG)4 is required for myocyte proliferation during early cardiac development. In the present study, we enrolled 80 unrelated patients with PA/VSD or TOF and identified a probably damaging variant p.T256M of NDRG4. The p.T256M variant impaired the proliferation ability of human cardiac myocytes (hCM). Furthermore, the p.T256M variant resulted in G1 and G2 arrest of hCM, followed by an increase in p27 and caspase‐9 expression. Our results provide evidence that the p.T256M variant in NDRG4 is a pathogenic variant associated with impaired hCM proliferation and cell‐cycle arrest and likely contributes towards the pathogenesis of PA/VSD and TOF.

DNA methylation markers detected in blood, stool, urine, and tissue in colorectal cancer: a systematic review of paired samples

PURPOSE

Methylated cell-free DNA in liquid biopsies are promising non-invasive biomarkers for colorectal cancer (CRC). Optimal markers would have high sensitivity and specificity for early detection of CRC and could be detected in more than one type of material from the patient. We systematically reviewed the literature on DNA methylation markers of colorectal cancer, detected in more than one type of material, regarding their potential as contributors to a panel for screening and follow-up of CRC.

METHODS

The databases MEDLINE, Web of Science, and Embase were systematically searched. Data extraction and review was performed by two authors independently. Agreement between methylation status in tissue and other materials (blood/stool/urine) was analyzed using the McNemar test and Cohen's kappa.

RESULTS

From the 51 included studies, we identified seven single markers with sensitivity ≥ 75% and specificity ≥ 90% for CRC. We also identified one promising plasma panel and two stool panels. The correspondence of methylation status was evaluated as very good for four markers, but only marginal for most of the other markers investigated (12 of 21).

CONCLUSION

The included studies reported only some of the variables and markers of interest and included few patients. Hence, a meta-analysis was not possible at this point. Larger, prospective studies must be designed to study the discordant detection of markers in tissue and liquid biopsies. When reporting their findings, such studies should use a standardized format.

A New Method for the Detection of Colorectal Cancer and the Precancerous Lesions: Occult Blood Testing Combination with Promoter Methylation in the Fecal Sample

Background: Noninvasive stool-based DNA methylation testing emerges as a new approach for detecting colorectal cancer (CRC). However, its feasibility for early detection of CRC and precancerous lesions in the Chinese population remains inconclusive.

Methods: In this study, we establish a possibilities screening method (sDNA-FOBT) for detecting CRC and precancerous lesions (hyperplastic polyps [HP] and adenomas [AD]) and evaluate its detection performance in the Chinese population. This method combined a molecular assay of DNA methylation markers (BMP3, NDRG4, and SDC2) with the human hemoglobin test (FOBT) in stool samples.

Results: The sensitivity of sDNA-FOBT was 85.42% for CRC, 85.71% for AD, and 28.21% for HP, respectively, at the specificity of 92%. The diagnostic efficacy of sDNA-FOBT for detecting CRC and precancerous lesions was significantly higher than FOBT alone (sensitivity: 61.70% vs. 51.06%, P<0.01; AUC: 0.78 vs. 0.72, P<0.001), especially for CRC (AUC: 0.91 vs. 0.86, P<0.001) and AD (AUC: 0.91 vs. 0.75, P<0.05). No significant difference was observed between the detection sensitivity of sDNA-FOBT and the clinical variables. Notably, compared with FOBT, sDNA-FOBT was more effective in the detection of CRC and precancerous lesions in the patients aged >50 y (62.34% vs 54.55%, P<0.05).

Conclusion: Our results demonstrate that sDNA-FOBT is a promising method for screening CRC and precancerous lesions in the Chinese population. Further studies are required to validate the results in a larger sample capacity.

Biomarkers for Early Detection of Colitis-associated Colorectal Cancer - Current Concepts, Future Trends

Colitis-associated colorectal cancer (CAC) remains a critical complication of ulcerative colitis (UC) with a mortality of approximately 15%, which makes early CAC diagnosis crucial. The current standard of surveillance, with repetitive colonoscopies and histological testing of biopsied mucosa samples, is burdensome and expensive, and therefore less invasive methods and reliable biomarkers are needed. Significant progress has been made, thanks to continuous extensive research in this field, however, no clinically relevant biomarker has been established so far. This review of the current literature presents the genetic and molecular differences between CAC and sporadic colorectal cancer and covers progress made in the early detection of CAC carcinogenesis. It focuses on biomarkers under development, which can easily be tested in samples of body fluids or breath and, once made clinically available, will help to differentiate between progressors (UC patients who will develop dysplasia) from non-progressors and enable early intervention to decrease the risk of cancer development.

The future of cancer screening after COVID-19 may be at home

LAY SUMMARY

During the coronavirus disease 2019 (COVID-19) pandemic, cancer screening decreased precipitously; home screening for colorectal cancer diminished less than that for colonoscopy and breast and cervical cancer screening. The authors have highlighted approaches for home cancer screening in addition to telemedicine.

Epigenetics of colorectal cancer: biomarker and therapeutic potential

Colorectal cancer (CRC), a leading cause of cancer-related death worldwide, evolves as a result of the stepwise accumulation of a series of genetic and epigenetic alterations in the normal colonic epithelium, leading to the development of colorectal adenomas and invasive adenocarcinomas. Although genetic alterations have a major role in a subset of CRCs, the pathophysiological contribution of epigenetic aberrations in this malignancy has attracted considerable attention. Data from the past couple of decades has unequivocally illustrated that epigenetic marks are important molecular hallmarks of cancer, as they occur very early in disease pathogenesis, involve virtually all key cancer-associated pathways and, most importantly, can be exploited as clinically relevant disease biomarkers for diagnosis, prognostication and prediction of treatment response. In this Review, we summarize the current knowledge on the best-studied epigenetic modifications in CRC, including DNA methylation and histone modifications, as well as the role of non-coding RNAs as epigenetic regulators. We focus on the emerging potential for the bench-to-bedside translation of some of these epigenetic alterations into clinical practice and discuss the burgeoning evidence supporting the potential of emerging epigenetic therapies in CRC as we usher in the era of precision medicine.

From Genetics to Epigenetics, Roles of Epigenetics in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a destructive, recurrent, and heterogeneous disease. Its detailed pathogenesis is still unclear, although available evidence supports that IBD is caused by a complex interplay between genetic predispositions, environmental factors, and aberrant immune responses. Recent breakthroughs with regard to its genetics have offered valuable insights into the sophisticated genetic basis, but the identified genetic factors only explain a small part of overall disease variance. It is becoming increasingly apparent that epigenetic factors can mediate the interaction between genetics and environment, and play a fundamental role in the pathogenesis of IBD. This review outlines recent genetic and epigenetic discoveries in IBD, with a focus on the roles of epigenetics in disease susceptibility, activity, behavior and colorectal cancer (CRC), and their potential translational applications.

Novel Methylated DNA Markers Discriminate Advanced Neoplasia in Pancreatic Cysts: Marker Discovery, Tissue Validation, and Cyst Fluid Testing

OBJECTIVES

Pancreatic cystic lesions (PCLs) may be precancerous. Those likely to harbor high-grade dysplasia (HGD) or pancreatic cancer (PC) are targets for surgical resection. Current algorithms to predict advanced neoplasia (HGD/PC) in PCLs lack diagnostic accuracy. In pancreatic tissue and cyst fluid (CF) from PCLs, we sought to identify and validate novel methylated DNA markers (MDMs) that discriminate HGD/PC from low-grade dysplasia (LGD) or no dysplasia (ND).

METHODS

From an unbiased whole-methylome discovery approach using predefined selection criteria followed by multistep validation on case (HGD or PC) and control (ND or LGD) tissues, we identified discriminant MDMs. Top candidate MDMs were then assayed by quantitative methylation-specific polymerase chain reaction on archival CF from surgically resected PCLs.

RESULTS

Of 25 discriminant MDMs identified in tissue, 13 were selected for validation in 134 CF samples (21 cases [8 HGD, 13 PC], 113 controls [45 ND, 68 LGD]). A tree-based algorithm using 2 CF-MDMs (TBX15, BMP3) achieved sensitivity and specificity above 90%. Discrimination was significantly better by this CF-MDM panel than by mutant KRAS or carcinoembryonic antigen, with areas under the receiver operating characteristic curve of 0.93 (95% confidence interval: 0.86-0.99), 0.71 (0.57-0.85), and 0.72 (0.60-0.84), respectively. Cutoffs for the MDM panel applied to an independent CF validation set (31 cases, 56 controls) yielded similarly high discrimination, areas under the receiver operating characteristic curve = 0.86 (95% confidence interval: 0.77-0.94, P = 0.2).

DISCUSSION

Novel MDMs discovered and validated in tissue accurately identify PCLs harboring HGD/PC. A panel of 2 MDMs assayed in CF yielded results with potential to enhance current risk prediction algorithms. Prospective studies are indicated to optimize and further evaluate CF-MDMs for clinical use.

Weak Cytotoxic T Cells Activation Predicts Low-Grade Dysplasia Persistence in Ulcerative Colitis

In patients with ulcerative colitis (UC), dysplasia develops in 10%–20% of cases. The persistence of low-grade dysplasia (LGD) in UC in 2 consecutive observations is still an indication for restorative proctocolectomy. Our hypothesis is that in the case of weak cytotoxic activation, dysplasia persists. We aimed to identify possible immunological markers of LGD presence and persistence.

Analysis of DNA Methylation at Specific Loci in Stool Samples Detects Colorectal Cancer and High-Grade Dysplasia in Patients With Inflammatory Bowel Disease

BACKGROUND & AIMS

Patients with inflammatory bowel diseases (IBDs), including ulcerative colitis and Crohn's disease, are at increased risk for colorectal cancer (CRC). Analyses of DNA methylation patterns in stool samples have been reported to detect CRC in patients with IBD. We sought to validate these findings in larger cohorts and assess the accuracy of analysis of DNA methylation patterns in stool for detection of CRC and high-grade dysplasia (HGD) normalized to methylation level at ZDHHC1.

METHODS

We obtained buffered, frozen stool samples from a US case-control study and from 2 European surveillance cohorts (referral or population based) of patients with chronic ulcerative colitis (n = 248), Crohn's disease (n = 82), indeterminate colitis (n = 2), or IBD with primary sclerosing cholangitis (n = 38). Stool samples were collected before bowel preparation for colonoscopy or at least 1 week after colonoscopy. Among the study samples, stools from individuals with IBD but without neoplasia were used as controls (n = 291). DNA was isolated from stool, exposed to bisulfite, and then assayed by multiplex quantitative allele-specific real-time target and signal amplification. We analyzed methylation levels of BMP3, NDRG4, VAV3, and SFMBT2 relative to the methylation level of ZDHHC1, and compared these between patients with CRC or HGD and controls.

RESULTS

Levels of methylation at BMP3 and VAV3, relative to ZDHHC1 methylation, identified patients with CRC and HGD with an area under the curve value of 0.91 (95% CI, 0.77-1.00). Methylation levels at specific promotor regions of these genes identified 11 of the 12 patients with CRC and HGD, with 92% sensitivity (95% CI, 60%-100%) and 90% specificity (95% CI, 86%-93%). The proportion of false-positive results did not differ significantly among the case-control, referral cohort, and population cohort studies (P = .60) when the 90% specificity cut-off from the whole sample set was applied.

CONCLUSIONS

In an analysis of stool samples from 3 independent studies of 332 patients with IBD, we associated levels of methylation at 2 genes (BMP3 and VAV3), relative to level of methylation at ZDHHC1, with detection of CRC and HGD. These methylation patterns identified patients with CRC and HGD with more than 90% specificity, and might be used in CRC surveillance.

A systematic review and quantitative assessment of methylation biomarkers in fecal DNA and colorectal cancer and its precursor, colorectal adenoma

Colorectal cancer (CRC) arises from accumulated genetic and epigenetic alterations, which provide the possibility to identify tumor-specific biomarkers by analyzing fecal DNA. Methylation status in human genes from tumor tissue is highlighted as promising biomarker in the early detection of CRC. A number of studies have documented altered methylation levels in DNA extracted from stool samples, but generated heterogeneous results. We performed a systematic review and quantitative assessment of existing studies to compare levels of DNA methylation in most frequently studied genes and their diagnostic value in CRC and its precursor, colorectal adenoma, with their counterparts in healthy subjects. Robust searches of the literature were performed in our study with explicit strategies and definite inclusion/exclusion criteria. Pooled data revealed that methylation levels of SFRP2, SFRP1, TFPI2, BMP3, NDRG4, SPG20, and BMP3 plus NDRG4 genes exceeded a sensitivity of 70% and a specificity of 80% for CRC detection. The DOR of the seven candidate biomarkers ranged from 19.80 to 334.33, indicating a good diagnostic power in discriminating cancer from normal tissues. The AUC range was from 0.88 to 0.95, indicating a good or very good discriminatory performance. When test results for BMP3 and NDRG4 were combined, the DOR of CRC detection was 98.36, which was higher than that for BMP3 and NDRG4 separately. As for adenoma detection, the DOR of methylated NDRG4 is higher than that for CRC (CRC vs. adenoma: 54.86 vs. 57.22). Both the sensitivity and specificity of NDRG4 for adenoma detection exceeded 70%. These findings demonstrate the eligibility and feasibility of DNA methylation as a minimally invasive biomarker in feces in the diagnosis of CRC and adenoma. The use of DNA from human stools has the potential to be readily applicable to detect aberrant DNA methylation levels among many subjects for CRC early screening.

An Overview of Molecular Profiles in Ulcerative Colitis-Related Cancer

Ulcerative colitis (UC) is an independent risk factor of colorectal cancer (CRC). Both genetic and epigentic events induce a unique molecular profile during the development from UC to UC-related CRC (UCRC). These molecular changes play varied roles in DNA repair, immune response, cell metabolism, and interaction with the microbiota during the carcinogenesis process. This review will systmatically discuss the molecular characteristics of UCRC and point out the future perspectives in this research field.

Early detection of ulcerative colitis-associated colorectal cancer

Colitis-associated colorectal cancer (CACC) is one of the most serious complications of inflammatory bowel disease (IBD), particularly in ulcerative colitis (UC); it accounts for approximately 15% of all-causes mortality among IBD patients. Because CACC shows a worse prognosis and higher mortality than sporadic colorectal cancer, early detection is critical. Colonoscopy is primarily recommended for surveillance and several advanced endoscopic imaging techniques are emerging. In addition, recent studies have reported on attempts to develop clinically relevant biomarkers for surveillance using various biosamples, which may become high-performance screening tools in the future, so the best approach and technique for cancer surveillance in long-standing UC patients remain under debate. This review gives a comprehensive description and summary about what progress has been made in terms of early CACC detection.

Colorectal Cancer in Inflammatory Bowel Disease

Patients with inflammatory bowel disease (IBD) are at significantly increased risk of colorectal cancer (CRC), principally resulting from the pro-neoplastic effects of chronic intestinal inflammation. Epidemiologic studies continue to highlight the increased risk of CRC in IBD. However, the incidence has declined over the past 30 years, attributed to both successful CRC-surveillance programs and improved control of mucosal inflammation. Risk factors that further increase the risk of IBD-related CRC include disease duration, extent and severity, the presence of inflammatory pseudopolyps, coexistent primary sclerosing cholangitis, and a family history of CRC. All major professional societies agree that IBD-CRC surveillance should occur more frequently than in the general population. Yet, guidelines and consensus statements differ on the surveillance schedule and preferred method of surveillance. Improved sensitivity to previously "invisible" flat dysplastic lesions using high definition and chromoendoscopy methods has resulted in many guidelines abandoning requirements for random untargeted biopsies of the colon. While colonic dysplasia remains a worrisome finding, and several clinical scenarios remain best addressed by total proctocolectomy due to concerns of synchronous undetected lesions and the unpredictable tempo of progression to malignancy, better detection techniques have also increased opportunities for endoscopic resection of dysplastic lesions that can be clearly delineated. Finally, the expanding armamentarium of medical options in IBD, including anti-tumor necrosis factor and anti-adhesion biologic therapies, have substantially improved our ability to control severe inflammation and likely reduce the risk of CRC over time.

Epigenomic biomarkers for prognostication and diagnosis of gastrointestinal cancers

Altered epigenetic regulation is central to many human diseases, including cancer. Over the past two decade, major advances have been made in our understanding of the role of epigenetic alterations in carcinogenesis, particularly for DNA methylation, histone modifications and non-coding RNAs. Aberrant hypermethylation of DNA at CpG islands is a well-established phenomenon that mediates transcriptional silencing of tumor suppressor genes, and it is an early event integral to gastrointestinal cancer development. As such, detection of aberrant DNA methylation is being developed as biomarkers for prognostic and diagnostic purposes in gastrointestinal cancers. Diverse tissue types are suitable for the analyses of methylated DNA, such as tumor tissues, blood, plasma, and stool, and some of these markers are already utilized in the clinical setting. Recent advances in the genome-wide epigenomic approaches are enabling the comprehensive mapping of the cancer methylome, thus providing new avenues for mining novel biomarkers for disease prognosis and diagnosis. Here, we review the current knowledge on DNA methylation biomarkers for the prognostication and non-invasive diagnosis of gastrointestinal cancers and highlight their clinical application.

An Update on Surveillance in Ulcerative Colitis

PURPOSE OF REVIEW

Patients with long-standing ulcerative colitis have an increased risk for the development of colorectal cancer (CRC). Colitis-related dysplasia appears to confer the greatest risk. Colonoscopic surveillance to detect dysplasia has been advocated by gastrointestinal societies. The aim of surveillance is the reduction of mortality and morbidity of CRC through detection and resection of dysplasia or detecting CRC at an earlier and potentially curable stage. Traditional surveillance has relied on mucosal assessment with targeted biopsy of visible lesions and random biopsy sampling on the premise that dysplasia was not visible at endoscopy. Advances in optical technology permitting increased detection of dysplasia and evidence that most dysplasia is visible has had practice-changing implications.

RECENT FINDINGS

Emerging evidence favours chromoendoscopy (CE) for dysplasia detection and is gaining wider acceptance through recent international (International Consensus Statement on Surveillance and Management of Dysplasia in Inflammatory Bowel Disease (SCENIC)) recommendations and endorsed by many gastrointestinal societies. Adoption of CE as the gold standard of surveillance has been met with by scepticism, from conflicting data, operational barriers and the need to understand the true impact of increasingly higher dysplasia detection on overall CRC mortality. Valid debate notwithstanding, implementation of a risk stratification protocol that includes CE is an effective approach allowing earlier detection of dysplasia and colorectal neoplasia, determination of surveillance intervals with appropriate allocation of resources and limiting morbidity from CRC and colonoscopy itself. Further prospective data should define the true and long-term impact of dysplasia detection with modern techniques.

Multi-target stool DNA test in the surveillance of inflammatory bowel disease: a cross-sectional cohort study

BACKGROUND AND AIM

Colonoscopic surveillance is recommended in patients with longstanding inflammatory bowel disease (IBD) as they are at increased risk of colorectal cancer (CRC). Non-invasive surveillance may improve compliance and access. Multi-target stool DNA (MT-sDNA) has been validated for screening of sporadic CRC but has not been assessed in IBD. Our aim was to assess the performance of a MT-sDNA test in a real-life surveillance setting of patients with longstanding IBD.

MATERIAL AND METHODS

A total of 192 IBD patients enrolled from two prospective cohorts submitted an EDTA buffered stool sample and underwent chromo- or white light colonoscopy. Stools were assayed for methylated BMP3 & NDRG4, mutant KRAS and β-actin by a laboratory blinded to clinical data.

RESULTS

The multitarget-sDNA panel was positive in 2/2 CRC and 5/15 low-grade dysplasia (LGD) < 1 cm in diameter. Sensitivities were 100% (95% CI 16-100%) for CRC and 33% (95% CI 13-61%) for LGD lesions <1 cm, with specificities of 87% (95% CI 81-91%) and 93% (95% CI 88-96%), respectively. The estimated number of patients needed to screen to detect a single CRC was 96 (95% CI 93-99%) and was 28 (95% CI 22-34%) to detect any colorectal neoplasia (CRN).

CONCLUSION

The MT-sDNA panel detected CRC in IBD. Sensitivity for sub-centimeter colorectal neoplasms in IBD patients appears similar to that observed in the general population. The test may be a valuable tool for detection of malignancy during structured surveillance of long-term IBD in a first line hospital setting.

KRAS and TP53 mutations in inflammatory bowel disease-associated colorectal cancer: a meta-analysis

Although KRAS and TP53 mutations are common in both inflammatory bowel disease-associated colorectal cancer (IBD-CRC) and sporadic colorectal cancer (S-CRC), molecular events leading to carcinogenesis may be different. Previous studies comparing the frequency of KRAS and TP53 mutations in IBD-CRC and S-CRC were inconsistent. We performed a meta-analysis to compare the presence of KRAS and TP53 mutations among patients with IBD-CRC, S-CRC, and IBD without dysplasia. A total of 19 publications (482 patients with IBD-CRC, 4,222 with S-CRC, 281 with IBD without dysplasia) met the study inclusion criteria. KRAS mutation was less frequent (RR=0.71, 95%CI 0.56-0.90; P=0.004) while TP53 mutation was more common (RR=1.24, 95%CI 1.10-1.39; P<0.001) in patients with IBD-CRC compared to S-CRC. Both KRAS (RR=3.09, 95%CI 1.47-6.51; P=0.003) and TP53 (RR=2.15, 95%CI 1.07-4.31 P=0.03) mutations were more prevalent in patients with IBD-CRC compared to IBD without dysplasia. In conclusion, IBD-CRC and S-CRC appear to have biologically different molecular pathways. TP53 appears to be more important than KRAS in IBD-CRC compared to S-CRC. Our findings suggest possible roles of TP53 and KRAS as biomarkers for cancer and dysplasia screening among patients with IBD and may also provide targeted therapy in patients with IBD-CRC.

Stool DNA Analysis is Cost-Effective for Colorectal Cancer Surveillance in Patients With Ulcerative Colitis

BACKGROUND & AIMS

Patients with chronic ulcerative colitis are at increased risk for colorectal neoplasia (CRN). Surveillance by white-light endoscopy (WLE) or chromoendoscopy may reduce risk of CRN, but these strategies are underused. Analysis of DNA from stool samples (sDNA) can detect CRN with high levels of sensitivity, but it is not clear if this approach is cost-effective. We simulated these strategies for CRN detection to determine which approach is most cost-effective.

METHODS

We adapted a previously published Markov model to simulate the clinical course of chronic ulcerative colitis, the incidence of cancer or dysplasia, and costs and benefits of care with 4 surveillance strategies: (1) analysis of sDNA and diagnostic chromoendoscopy for patients with positive results, (2) analysis of sDNA with diagnostic WLE for patients with positive results, (3) chromoendoscopy with targeted collection of biopsies, or (4) WLE with random collection of biopsies. Costs were based on 2014 Medicare reimbursement. The primary outcome was the incremental cost-effectiveness ratio (incremental cost/incremental difference in quality-adjusted life-years) compared with no surveillance and a willingness-to-pay threshold of $50,000.

RESULTS

All strategies fell below the willingness-to-pay threshold at 2-year intervals. Incremental cost-effectiveness ratios were $16,362 per quality-adjusted life-year for sDNA analysis with diagnostic chromoendoscopy; $18,643 per quality-adjusted life-year for sDNA analysis with diagnostic WLE; $23,830 per quality-adjusted life-year for chromoendoscopy alone; and $27,907 per quality-adjusted life-year for WLE alone. In sensitivity analyses, sDNA analysis with diagnostic chromoendoscopy was more cost-effective than chromoendoscopy alone, up to a cost of $1135 per sDNA test. sDNA analysis remained cost-effective at all rates of compliance; when combined with diagnostic chromoendoscopy, this approach was preferred over chromoendoscopy alone, when the specificity of the sDNA test for CRN was >65%.

CONCLUSIONS

Based on a Markov model, surveillance for CRN is cost-effective for patients with chronic ulcerative colitis. Analysis of sDNA with chromoendoscopies for patients with positive results was more cost-effective than chromoendoscopy or WLE alone.

Advanced imaging in colonoscopy: contemporary approach to dysplasia surveillance in inflammatory bowel disease

Inflammatory bowel disease (IBD) (ulcerative colitis (UC) and Crohn's disease (CD)) is a chronic relapsing/remitting condition characterised by intestinal inflammation. One of the main concerns in patients with longstanding ulcerative and Crohn's colitis is development of colonic dysplasia and colorectal cancer (CRC), a risk higher than that of the general population. Colonoscopy surveillance programmes have been developed by major societies worldwide to improve early dysplasia detection and treatment, thus preventing progression to colorectal cancer. Colonoscopy is an imperfect tool as lesions can be missed, an issue even more relevant to colitic patients, where mucosal inspection and lesion recognition may prove challenging. Extensive research has been undertaken on performance improvement in this area while technical advances in optical imaging, such as high-definition, have made their way into modern endoscopy units. Techniques and technologies available to enhance optical diagnosis of dysplasia in inflammatory bowel disease are reviewed in this paper, focusing on those that are realistic, widely available and feasible for everyday practice.

Colorectal Cancer and Dysplasia in Inflammatory Bowel Disease: A Review of Disease Epidemiology, Pathophysiology, and Management

Crohn disease and ulcerative colitis are chronic inflammatory bowel diseases (IBD) characterized by recurrent episodes of mucosal inflammation. This chronic mucosal inflammation has several potential consequences, one of which is the occurrence of colitis-associated colorectal cancer. Over the past decade, our understanding of the epidemiology, pathophysiology, and overall approach to diagnosing and managing colitis-associated colorectal cancer has grown considerably. In the current review article, we outline these advancements and highlight areas in need of further research. Cancer Prev Res; 9(12); 887-94. ©2016 AACR.

Genomics of Colorectal Cancer in African Americans

Genome-wide studies are increasingly becoming a must, especially for complex diseases such as cancer where multiple genes and diverse molecular mechanisms are known to be involved in genes' function alteration. In this review, we report our latest genomic and epigenomic findings in African-American colorectal cancer patients. This population suffers a higher burden of the disease and most investigators in this field are looking for the underlying genetic and epigenetic targets that might be responsible for this disparity. We here report genome-wide copy number variations, single nucleotide mutations and DNA methylation findings that might be specific to this population.

Biomarkers for colitis-associated colorectal cancer

Patients with extensive ulcerative colitis (UC) of more than eight years duration have an increased risk of colorectal cancer. Molecular biomarkers for dysplasia and cancer could have a great clinical value in managing cancer risk in these UC patients. Using a wide range of molecular techniques - including cutting-edge OMICS technologies - recent studies have identified clinically relevant biomarker candidates from a variety of biosamples, including colonic biopsies, blood, stool, and urine. While the challenge remains to validate these candidate biomarkers in multi-center studies and with larger patient cohorts, it is certain that accurate biomarkers of colitis-associated neoplasia would improve clinical management of neoplastic risk in UC patients. This review highlights the ongoing avenues of research in biomarker development for colitis-associated colorectal cancer.

Molecular Detection of Gastrointestinal Neoplasia: Innovations in Early Detection and Screening

Emerging molecular tools promise to extend the diagnostic reach of the endoscopist and open doors to population screening for gastrointestinal (GI) cancers. This review briefly addresses biological considerations in marker detection and types of markers, highlights examples of tools under development at each organ site, and appraises the possibility of universal GI cancer screening. The outlook is positive, but further technical refinement and rigorous clinical validation are needed before most of these new approaches are ready for clinical application.

DNA Methylation and Mutation of Small Colonic Neoplasms in Ulcerative Colitis and Crohn's Colitis: Implications for Surveillance

BACKGROUND

Stool DNA testing in patients with inflammatory bowel disease (IBD) may detect colorectal cancer and advanced precancers with high sensitivity; less is known about the presence of DNA markers in small IBD lesions, their association with metachronous neoplasia, or contribution to stool test positivity.

METHODS

At a single center in 2 blinded phases, we assayed methylated bone morphogenic protein 3, methylated N-Myc downstream-regulated gene 4, and mutant KRAS in DNA extracted from paraffin-embedded benign lesions, and matched control tissues of patients with IBD, who were followed for subsequent colorectal dysplasia. Stool samples from independent cases and controls with lesions <1 cm or advanced neoplasms were assayed for the same markers.

RESULTS

Among IBD lesions (29 low-grade dysplasia, 19 serrated epithelial change, and 10 sessile serrated adenoma/polyps), the prevalence of methylation was significantly higher than in mucosae from 44 matched IBD controls (P < 0.0001 for methylated bone morphogenic protein 3 or methylated N-Myc downstream-regulated gene 4). KRAS mutations were more abundant in serrated epithelial change than all other groups (P < 0.001). Subsequent dysplasia was not associated with DNA marker levels. In stools, the sensitivity of methylated bone morphogenic protein 3 as a single marker was 60% for all lesions <1 cm, 63% for low-grade dysplasia ≥1 cm and 81% for high-grade dysplasia/colorectal cancer, all at 91% specificity (P < 0.0001).

CONCLUSIONS

Selected DNA markers known to be present in advanced IBD neoplasia can also be detected in both tissues and stools from IBD patients with small adenomas and serrated lesions. Mutant KRAS exfoliated from serrated epithelial change lesions might raise false-positive rates. These findings have relevance to potential future applications of stool DNA testing for IBD surveillance.

Ulcerative Colitis: Update on Medical Management

Ulcerative colitis (UC) is a chronic inflammatory bowel disease whose pathogenesis is multifactorial and includes influences from genes, the environment, and the gut microbiome. Recent advances in diagnosis and treatment have led to significant improvement in managing the disease. Disease monitoring with the use of therapeutic drug monitoring, stool markers, and assessment of mucosal healing have garnered much attention. The recent approval of vedolizumab for treatment of moderate to severe UC has been a welcome addition. Newer biologics, including those targeting the Janus tyrosine kinase (JAK) pathway, are on the horizon to add to the current armamentarium of anti-TNF alpha and anti-integrin therapies. The recent publication of the SCENIC consensus statement on surveillance and management of dysplasia in UC patients supports the use of chromoendoscopy over random biopsies in detecting dysplasia. This review highlights these recent advances along with others that have been made with ulcerative colitis.

Hypermethylated DNA as a biomarker for colorectal cancer: a systematic review

AIM

Improved methods for early detection of colorectal cancer (CRC) are essential for increasing survival. Hypermethylated DNA in blood or stool has been proposed as a biomarker for CRC. Biochemical methods have improved in recent years, and several hypermethylated genes that are sensitive and specific for CRC have been proposed. Articles describing the use of hypermethylated promoter regions in blood or stool as biomarkers for CRC were systematically reviewed.

METHOD

A systematic literature search was performed using the Medline, Web of Science and Embase databases. Studies were included if they analysed hypermethylated genes from stool or blood samples in correlation with CRC. Studies in languages other than English and those based on animal models or cell lines were excluded.

RESULTS

The literature search yielded 74 articles, including 43 addressing blood samples and 31 addressing stool samples. In blood samples, hypermethylated ALX4, FBN2, HLTF, P16, TMEFF1 and VIM were associated with poor prognosis, hypermethylated APC, NEUROG1, RASSF1A, RASSF2A, SDC2, SEPT9, TAC1 and THBD were detected in early stage CRC and hypermethylated P16 and TFPI2 were associated with CRC recurrence. In stool samples, hypermethylated BMP3, PHACTR3, SFRP2, SPG20, TFPI2 and TMEFF2 were associated with early stage CRC.

CONCLUSION

Hypermethylation of the promoters of specific genes measured in blood or stool samples could be used as a CRC biomarker and provide prognostic information. The majority of studies, however, include only a few patients with poorly defined control groups. Further studies are therefore needed before hypermethylated DNA can be widely applied as a clinical biomarker for CRC detection and prognosis.

[Current principles in the screening, diagnosis, and therapy of colorectal cancer]

The data available in the literature on the prevalence of colorectal cancer (CRC), its risk factors and genetic aspects are analyzed. Basic screening tests and their diagnostic value are described. The paper indicates the importance of methods (colonoscopy, occult blood feces analysis, fecal immunochemical test, determination of molecular genetic profile of fecal enterocytes) for the early primary diagnosis of colonic epithelial tumors and techniques (echography, computed tomography, magnetic resonance imaging, positron emission tomography) that are required to specify clinical TNM staging and enable one to choose an optimal treatment policy for CRC patients owing to the estimation of tumor volume and to the diagnosis of reginal and distant metastases. It also shows that new screening methods based on the detection of molecular markers for early (premorphological) tumor stages are promising. The role of primary CRC prevention aimed at molding and maintaining a healthy lifestyle in the population is demonstrated.

Aberrant gene methylation in non-neoplastic mucosa as a predictive marker of ulcerative colitis-associated CRC

BACKGROUND PROMOTER: hypermethylation plays a major role in cancer through transcriptional silencing of critical genes. The aim of our study is to evaluate the methylation status of these genes in the colonic mucosa without dysplasia or adenocarcinoma at the different steps of sporadic and UC-related carcinogenesis and to investigate the possible role of genomic methylation as a marker of CRC.

RESULTS

The expression of Dnmts 1 and 3A was significantly increased in UC-related carcinogenesis compared to non inflammatory colorectal carcinogenesis. In non-neoplastic colonic mucosa, the number of methylated genes resulted significantly higher in patients with CRC and in those with UC-related CRC compared to the HC and UC patients and patients with dysplastic lesion of the colon. The number of methylated genes in non-neoplastic colonic mucosa predicted the presence of CRC with good accuracy either in non inflammatory and inflammatory related CRC.

METHODS

Colonic mucosal samples were collected from healthy subjects (HC) (n = 30) and from patients with ulcerative colitis (UC) (n = 29), UC and dysplasia (n = 14), UC and cancer (n = 10), dysplastic adenoma (n = 14), and colon adenocarcinoma (n = 10). DNA methyltransferases-1, -3a, -3b, mRNA expression were quantified by real time qRT-PCR. The methylation status of CDH13, APC, MLH1, MGMT1 and RUNX3 gene promoters was assessed by methylation-specific PCR.

CONCLUSIONS

Methylation status of APC, CDH13, MGMT, MLH1 and RUNX3 in the non-neoplastic mucosa may be used as a marker of CRC: these preliminary results could allow for the adjustment of a patient's surveillance interval and to select UC patients who should undergo intensive surveillance.

How to improve colon cancer screening rates

Colorectal carcinoma is a common cause of death throughout the world and may be prevented by routine control, which can detect precancerous neoplasms and early cancers before they undergo malignant transformation or metastasis. Three strategies may improve colon cancer screening rates: convince the population about the importance of undergoing a screening test; achieve higher efficacy in standard screening tests and make them more available to the community and develop new more sensitive and efficacious screening methods and make them available as routine tests. In this light, the present study seeks to review these three means through which to increase colon cancer screening rates.

Value of DNA methylation markers in colorectal cancer screening

Colorectal cancer (CRC) is one of the most common malignant tumors in the world. Recognizing CRC at an early stage by population-based screening is crucial in the prevention and treatment of CRC. Numerous candidate genes, which play important roles in the development and progression of CRC, have been found to be hyper-methylated in the promoter regions in recent studies. The promoter fragments of those hyper-methylated genes in tumor tissues have also been detected in the blood and fecal specimens, with higher sensitivity and specificity than traditional markers in the screening of CRC, including carcino-embryonic antigen (CEA) and fecal occult blood test. Here, we will discuss what we have already known about the DNA methylation markers for CRC screening and the potential research direction in the future.

Fecal DNA testing for colorectal cancer screening: Molecular targets and perspectives

The early detection of colorectal cancer with effective screening is essential for reduction of cancer-specific mortality. The addition of fecal DNA testing in the armamentarium of screening methods already in clinical use launches a new era in the noninvasive part of colorectal cancer screening and emanates from a large number of previous and ongoing clinical investigations and technological advancements. In this review, we discuss the molecular rational and most important genetic alterations hallmarking the early colorectal carcinogenesis process. Also, representative DNA targets-markers and key aspects of their testing at the clinical level in comparison or/and association with other screening methods are described. Finally, a critical view of the strengths and limitations of fecal DNA tests is provided, along with anticipated barriers and suggestions for further exploitation of their use.

Epigenetic Alterations in Colorectal Cancer: Emerging Biomarkers

Colorectal cancer (CRC) is a leading cause of cancer deaths worldwide. One of the fundamental processes driving the initiation and progression of CRC is the accumulation of a variety of genetic and epigenetic changes in colonic epithelial cells. Over the past decade, major advances have been made in our understanding of cancer epigenetics, particularly regarding aberrant DNA methylation, microRNA (miRNA) and noncoding RNA deregulation, and alterations in histone modification states. Assessment of the colon cancer "epigenome" has revealed that virtually all CRCs have aberrantly methylated genes and altered miRNA expression. The average CRC methylome has hundreds to thousands of abnormally methylated genes and dozens of altered miRNAs. As with gene mutations in the cancer genome, a subset of these epigenetic alterations, called driver events, are presumed to have a functional role in CRC. In addition, the advances in our understanding of epigenetic alterations in CRC have led to these alterations being developed as clinical biomarkers for diagnostic, prognostic, and therapeutic applications. Progress in this field suggests that these epigenetic alterations will be commonly used in the near future to direct the prevention and treatment of CRC.

Molecular markers for colorectal cancer screening

Colorectal cancer (CRC), although a significant cause of morbidity and mortality worldwide, has seen a declining incidence and mortality in countries with programmatic screening. Faecal occult blood testing and endoscopic approaches are the predominant screening methods currently. The discovery of the adenoma-carcinoma sequence and a greater understanding of the genetic and epigenetic changes that drive the formation of CRC have contributed to innovative research to identify molecular markers for highly accurate, non-invasive screening tests for CRC. DNA, proteins, messenger RNA and micro-RNA have all been evaluated. The observation of tumour cell exfoliation into the mucocellular layer of the colonic epithelium and proven stability of DNA in a harsh stool environment make stool DNA a particularly promising marker. The development of a clinically useful stool DNA test has required numerous technical advances, including optimisation in DNA stabilisation, the development of assays with high analytical sensitivity, and the identification of specific and broadly informative molecular markers. A multitarget stool DNA test, which combines mutant and methylated DNA markers and a faecal immunochemical test, recently performed favourably in a large cross-sectional validation study and has been approved by the US Food and Drug Administration for the screening of asymptomatic, average-risk individuals. The ultimate way in which molecular marker screening assays will be used in clinical practice will require additional studies to determine optimal screening intervals, factors affecting compliance, management of false-positive results, and the use of these assays in high-risk populations, as well as other considerations.