Colorectal adenoma and cancer detection based on altered methylation pattern of SFRP1, SFRP2, SDC2, and PRIMA1 in plasma samples

Effectiveness of single-target fecal DNA methylation test in regional mass screening for colorectal cancer and precancerous lesions in China

Background

Colorectal cancer (CRC) is the third-most-common malignancy and the second-leading cause of cancer-related deaths worldwide and current screening methods such as guaiac-based fecal occult blood test (gFOBT), fecal immunochemical test (FIT), and colonoscopy have their own pros and cons. This study aimed to assess the effectiveness of a fecal DNA methylation test by using methylated SDC2 (mSDC2) as the epigenetic biomarker for detecting CRC in a screening-naïve population.

Methods

Fecal mSDC2 test and FIT were simultaneously performed on eligible 40- to 74-year-old adults of a regional township in China. Subjects with positive results were recommended for colonoscopy. Data of positivity rates, positive predicted values (PPVs), and detection rates associated with clinical characteristics were analysed.

Results

The positivity rate of mSDC2 was 7.6% for 10,578 participants with valid results from both fecal mSDC2 test and FIT. With an adherence rate of 63.8% to colonoscopy referral, 25 CRCs, 189 advanced adenomas (AAs), and 165 non-advanced adenomas (NAAs) and polyps were detected. The PPVs of mSDC2 were 4.93%, 37.28%, and 32.54% for CRC, AA, and non-advanced lesions, respectively. When the CRCs and AAs were counted as positive findings, the fecal mSDC2 test showed a higher detective rate than FIT (relative risk [RR], 1.313 [1.129-1.528], P < 0.001). When NAAs and polyps were also specified as treatable lesions, the mSDC2 test was more effective in detecting these benign growths (RR, 1.872 [1.419-2.410]; P < 0.001). A combination of mSDC2 and FIT detected 29 CRCs, 298 AAs, and 234 NAAs and polyps. Overall, the fecal mSDC2 test had a higher detection rate for both advanced and non-advanced colonic lesions. The false-positive rate of the fecal mSDC2 test was comparable to that of FIT (RR, 1.169 [0.974-1.403]; P = 0.113).

Conclusions

The single-target stool-based mSDC2 test can effectively and accurately detect CRC and precancerous lesions in a large-scale CRC-screening program.

Trial registration number

NCT05374369.

Dysregulation of DNA methylation in colorectal cancer: biomarker, immune regulation, and therapeutic potential

Colorectal cancer (CRC) is one of the most prevalent malignancies worldwide, with morbidity and mortality ranking third and second among all cancers, respectively. As a result of a sequence of genetic and DNA methylation alterations that gradually accumulate in the healthy colonic epithelium, colorectal adenomas and invasive adenocarcinomas eventually give rise to CRC. Global hypomethylation and promoter-specific DNA methylation are characteristics of CRC. The pathophysiological role of aberrant DNA methylation in malignant tumors has garnered significant interest in the last few decades. In addition, DNA methylation has been shown to play a critical role in influencing immune cell function and tumor immune evasion. This review summarizes the most recent research on DNA methylation changes in CRC, including the role of DNA methylation-related enzymes in CRC tumorigenesis and biomarkers for diagnosis, predictive and prognostic. Besides, we focus on the emerging potential of epigenetic interventions to enhance antitumor immune responses and improve the CRC clinical practice.

Research Progress of Liquid Biopsy Based on DNA Methylation in Tumor Diagnosis and Treatment

Liquid biopsy has been gradually applied to the clinical diagnosis and treatment of tumors because of its non-invasive and real-time reflection of the tumor status, as well as the convenience of sample collection, which allows the detection of primary or metastatic malignant tumors and reflects the heterogeneity of the tumors. DNA methylation, which is a type of epigenetic modification, is essential in the progression of tumors. This review introduces the common DNA methylation analysis methods and discusses their advantages and disadvantages, focusing on the new progress of DNA methylation-based liquid biopsy in tumor diagnosis and treatment.

Clinical Applications of Circulating Tumor DNA Profiling in GI Cancers

Over the next few years, the analysis of circulating tumor DNA (ctDNA) through liquid biopsy is expected to enter clinical practice and revolutionize the approach to biomarker testing and treatment selection in GI cancers. In fact, growing evidence support the use of ctDNA testing as a noninvasive, effective, and highly specific tool for molecular profiling in GI cancers. Analysis of blood ctDNA has been investigated in multiple settings including early tumor detection, minimal residual disease evaluation, tumor diagnosis and evaluation of prognostic/predictive biomarkers for targeted treatment selection, longitudinal monitoring of treatment response, and identification of resistance mechanisms. Here, we review the clinical applications, advantages, and limitations of ctDNA profiling for precision oncology in GI cancers.

Performance of DNA methylation and blood-borne tumor indicators in detecting colorectal neoplasia and adenomas: a comparative study with the fecal occult blood test

Objectives

To evaluate the performance of stool methylated syndecan2 (mSDC2), methylated septin9 (mSEPT9), fecal occult blood test (FOBT), carcinoembryonic antigen (CEA), carbohydrate antigen 125 (CA125) and carbohydrate antigen 199 (CA199) in detecting colorectal neoplasia and adenomas.

Methods

Blood-borne CEA, CA125, and CA199 levels were measured by electrochemiluminescence. The SDC2 methylation was detected by Methylation Detection Kit for Human SDC2 Gene (Real time PCR), and the SEPT9 methylation was detected by the Septin9 Gene Methylation Detection Kit based on PCR fluorescent probe assay. The colonoscopy combined with tissue biopsy pathology was used as a validation criterion for colorectal neoplasia.

Results

In detecting colorectal neoplasia, the AUCs of mSDC2, FOBT and mSEPT9 were 0.935 (95% CI: 0.915-0.956, P<0.001), 0.824 (95% CI: 0.617-1.000, P<0.001) and 0.671 (95% CI: 0.511-0.831, P<0.001), respectively. The sensitivity of mSDC2, FOBT and mSEPT9 were 100.0%, 66.7% and 40.0%, respectively. But the AUC of CEA, CA125 and CA199 were not statistically significant for colorectal neoplasia (all P>0.05). The combined application of mSEPT9 and mSDC2 showed the best predictive performance (AUC: 0.956, 95% CI: 0.887~1.000). For adenomas, the AUC of FOBT was extremely low (AUC: 0.524, 95% CI: 0.502-0.545, P=0.004). The CEA, CA125, CA199, mSEPT9 and mSDC2 were not statistically significant in detecting adenomas (all P>0.05).

Conclusions

For individual tests, FOBT and mSDC2 are relatively better indicators for detecting colorectal neoplasia compared to mSEPT9, CEA, CA125 and CA199. The combined form of mSEPT9 and mSDC2 to detect colorectal neoplasia has good predictive performance. However, none of these indicators demonstrated significant predictive power for detecting adenomas in our study.

The prognostic role of circulating tumour DNA detected prior to clinical diagnosis of colorectal cancer in the HUNT study

BACKGROUND

Today, the prognostic tools available at the time of diagnosis in colorectal cancer (CRC) are limited. Better prognostic tools are a prerequisite for personalised treatment. This study aimed to investigate whether circulating tumour DNA (ctDNA) markers found in plasma before clinical diagnosis of CRC could contribute to the prediction of poor prognosis.

METHODS

This observational cohort study included patients diagnosed with CRC stage I-III within 24 months following participation in the Trøndelag Health Study (n = 85). Known methylated ctDNA biomarkers of CRC were analysed by PCR in plasma. Outcomes were overall survival (OS), recurrence-free survival (RFS) and poor prognosis (PP). Candidate clinical and methylated ctDNA predictors of the outcomes were identified by Cox regression analyses.

RESULTS

Methylated GRIA4 (HR 1.96 (1.06-3.63)), RARB (HR 9.48 (3.00-30.00)), SLC8A1 (HR 1.97 (1.03-3.77)), VIM (HR 2.95 (1.22-7.14)) and WNT5A (HR 5.83 (2.33-14.56)) were independent predictors of OS, methylated RARB (HR 9.67 (2.54-36.81)), SDC2 (HR 3.38 (1.07-10.66)), SLC8A1 (HR 2.93 (1.01-8.51)) and WNT5A (HR 6.95 (1.81-26.68)) were independent predictors of RFS and methylated RARB (HR 6.11 (1.69-22.18)), SDC2 (HR 2.79 (1.20-6.49)) and WNT5A (HR 5.57 (3.04-15.26)) were independent predictors of PP (p < 0.05).

CONCLUSIONS

Prediagnostic ctDNA markers are promising contributors to predicting poor prognosis in CRC, potentially becoming one of the tools guiding more personalised treatment.

Evaluation of Multigene Methylation for Blood-Based Detection of Colorectal Cancer

Background: Early screening for colorectal cancer (CRC) has the potential to improve patient prognosis, but current screening methods are limited. In this prospective study, we aimed to evaluate the multigene (Septin9, SDC2, KCNQ5, and IKZF1) detection in patient plasma for CRC diagnosis. Methods: Overall, 67 participants were enrolled, including 31 patients with CRC, 17 patients with colorectal polyp, and 19 normal controls who underwent colonoscopy. Carcinoembryonic antigen (CEA) and Septin9, SDC2, KCNQ5, and IKZF1 methylation tests were performed. Sensitivity, specificity, and the area under the receiver operating characteristic (ROC) curve were used to evaluate the diagnostic value of each biomarker. The association between positive rates of methylated Septin9, SDC2, KCNQ5, and IKZF1 and the clinicopathological characteristics of CRC was also analyzed. Results: The positive rate of multigene methylation detection was 87.1% (27/31) in patients with CRC, which was higher than single indicators: CEA (51.61%, 16/31), Septin9 (41.94%, 13/31), SDC2 (41.94%, 13/31), KCNQ5 (58.06%, 18/31), and IKZF1 (32.26%, 10/31). In the colorectal polyp group, the rate of multigene methylation detection is 88.24% (15/17), which was also higher than single indicator: CEA (17.65%, 3/17), Septin9 (11.76%, 2/17), SDC2 (64.71%, 11/17), KCNQ5 (58.82%, 10/17), and IKZF1 (35.29%, 6/17). The ROC curves further showed better diagnostic value of the multigene test for CRC than any single gene. Correlation analysis found that the positive rate of the test was not affected by patients' clinicopathologic characteristics. Conclusion: The combination of methylated Septin9, SDC2, KCNQ5, and IKZF1 tests is preferable to individual gene tests for patients with CRC and polyp.

Personalised medicine based on host genetics and microbiota applied to colorectal cancer

Colorectal cancer (CRC) ranks second in incidence and third in cancer mortality worldwide. This situation, together with the understanding of the heterogeneity of the disease, has highlighted the need to develop a more individualised approach to its prevention, diagnosis and treatment through personalised medicine. This approach aims to stratify patients according to risk, predict disease progression and determine the most appropriate treatment. It is essential to identify patients who may respond adequately to treatment and those who may be resistant to treatment to avoid unnecessary therapies and minimise adverse side effects. Current research is focused on identifying biomarkers such as specific mutated genes, the type of mutations and molecular profiles critical for the individualisation of CRC diagnosis, prognosis and treatment guidance. In addition, the study of the intestinal microbiota as biomarkers is being incorporated due to the growing scientific evidence supporting its influence on this disease. This article comprehensively addresses the use of current and emerging diagnostic, prognostic and predictive biomarkers in precision medicine against CRC. The effects of host genetics and gut microbiota composition on new approaches to treating this disease are discussed. How the gut microbiota could mitigate the side effects of treatment is reviewed. In addition, strategies to modulate the gut microbiota, such as dietary interventions, antibiotics, and transplantation of faecal microbiota and phages, are discussed to improve CRC prevention and treatment. These findings provide a solid foundation for future research and improving the care of CRC patients.

Clinical application of liquid biopsy in colorectal cancer: detection, prediction, and treatment monitoring

Colorectal cancer (CRC) is one of the most prevalent malignancies affecting the gastrointestinal tract and is ranked third among cancers with the highest incidence and second-highest mortality rate worldwide. CRC exhibits a slow progression providing a wide treatment window. The currently employed CRC screening methods have shown great potential to prevent CRC and reduce CRC-related morbidity and mortality. The diagnosis of CRC is achieved by colonoscopy and tissue biopsy, with studies showing that liquid biopsy is more effective in detecting and diagnosing early CRC patients. Increasing number of studies have shown that the tumor components shed into circulating blood can be detected in liquid form, and can be applied in the clinical management of CRC. Analysis of circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), or tumor-associated platelets (TEPs) in the blood can be used for early screening and diagnosis of CRC, aid tumor staging, treatment response monitoring, and prediction of CRC recurrence and metastasis in a minimally invasive manner. This chapter provides an updated review of CTCs, ctDNA, and TEPs as novel biomarkers for CRC, highlighting their strengths and limitations.

DNA methylation in human diseases

Aberrant epigenetic modifications, particularly DNA methylation, play a critical role in the pathogenesis and progression of human diseases. The current review aims to reveal the role of aberrant DNA methylation in the pathogenesis and progression of diseases and to discuss the original data obtained from international research laboratories on this topic. In the review, we mainly summarize the studies exploring the role of aberrant DNA methylation as diagnostic and prognostic biomarkers in a broad range of human diseases, including monogenic epigenetics, autoimmunity, metabolic disorders, hematologic neoplasms, and solid tumors. The last section provides a general overview of the possibility of the DNA methylation machinery from the perspective of pharmaceutic approaches. In conclusion, the study of DNA methylation machinery is a phenomenal intersection that each of its ways can reveal the mysteries of various diseases, introduce new diagnostic and prognostic biomarkers, and propose a new patient-tailored therapeutic approach for diseases.

Pathogenesis and biomarkers of colorectal cancer by epigenetic alteration

Colorectal cancer (CRC) ranks third in cancer incidence and stands as the second leading cause of cancer-related deaths globally. CRC tumorigenesis results from a cumulative set of genetic and epigenetic alterations, disrupting cancer-regulatory processes like cell proliferation, metabolism, angiogenesis, cell death, invasion, and metastasis. Key epigenetic modifications observed in cancers encompass abnormal DNA methylation, atypical histone modifications, and irregularities in noncoding RNAs, such as microRNAs and long noncoding RNAs. The advancement in genomic technologies has positioned these genetic and epigenetic shifts as potential clinical biomarkers for CRC patients. This review concisely covers the fundamental principles of CRC-associated epigenetic changes, and examines in detail their emerging role as biomarkers for early detection, prognosis, and treatment response prediction.

DNA methylation modulates epigenetic regulation in colorectal cancer diagnosis, prognosis and precision medicine

Colorectal cancer (CRC) is a multifaceted disease influenced by the interplay of genetic and environmental factors. The clinical heterogeneity of CRC cannot be attributed exclusively to genetic diversity and environmental exposures, and epigenetic markers, especially DNA methylation, play a critical role as key molecular markers of cancer. This review compiles a comprehensive body of evidence underscoring the significant involvement of DNA methylation modifications in the pathogenesis of CRC. Moreover, this review explores the potential utility of DNA methylation in cancer diagnosis, prognostics, assessment of disease activity, and prediction of drug responses. Recognizing the impact of DNA methylation will enhance the ability to identify distinct CRC subtypes, paving the way for personalized treatment strategies and advancing precision medicine in the management of CRC.

Advances in blood DNA methylation-based assay for colorectal cancer early detection: a systematic updated review

Aim

A systematic review was conducted to summarize the methylated circulating tumor DNA (ctDNA) markers reported over the last decade for early detection of colorectal cancer (CRC) and to identify the main technical challenges that are impeding their clinical implementation.

Background

CRC is a major cause of cancer deaths worldwide, but early detection is key for successful treatment. Non-invasive methods such as methylated ctDNA testing show promise for improving detection and monitoring of CRC.

Methods

A comprehensive search was performed using Web of Science, PubMed, and Scopus up to December 30, 2023, limited to articles published in the last 10 years (after 2012), while including advanced adenoma/stage 0 or stage I/II samples in biomarker validation.

Results

After identifying 694 articles, removing duplicates and screening titles, abstracts, and full texts, a total of 62 articles were found to meet the inclusion criteria. Among the single biomarkers, MYO1-G, SEPT9, SDC2, and JAM3 revealed the highest sensitivity for polyps and stage I/II CRC. For multi-biomarkers with suitable sensitivity, combinations of SFRP1, SFRP2, SDC2, PRIMA1, or ALX4, BMP3, NPTX2, RARB, SDC2, SEPT9, VIM or ZFHX4, ZNF334, ELOVL2, UNC5C, LOC146880, SFMBT2, GFRA1 were identified for polyps and stage I/II CRC.

Conclusion

Enhancing sensitivity and specificity of molecular screening methods is crucial for improving CRC detection. Identifying a select few valuable biomarkers is key to reducing costs, despite challenges posed by low ctDNA levels in plasma, particularly in early-stage cancers.

A novel screening method of DNA methylation biomarkers helps to improve the detection of colorectal cancer and precancerous lesions

BACKGROUND

Colorectal cancer (CRC) is one of the most common malignancies, and early detection plays a crucial role in enhancing curative outcomes. While colonoscopy is considered the gold standard for CRC diagnosis, noninvasive screening methods of DNA methylation biomarkers can improve the early detection of CRC and precancerous lesions.

METHODS

Bioinformatics and machine learning methods were used to evaluate CRC-related genes within the TCGA database. By identifying the overlapped genes, potential biomarkers were selected for further validation. Methylation-specific PCR (MSP) was utilized to identify the associated genes as biomarkers. Subsequently, a real-time PCR assay for detecting the presence of neoplasia or cancer of the colon or rectum was established. This screening approach involved the recruitment of 978 participants from five cohorts.

RESULTS

The genes with the highest specificity and sensitivity were Septin9, AXL4, and SDC2. A total of 940 participants were involved in the establishment of the final PCR system and the subsequent performance evaluation test. A multiplex TaqMan real-time PCR system has been illustrated to greatly enhance the ability to detect precancerous lesions and achieved an accuracy of 87.8% (95% CI 82.9-91.5), a sensitivity of 82.7% (95% CI 71.8-90.1), and a specificity of 90.1% (95% CI 84.3-93.9). Moreover, the detection rate of precancerous lesions of this assay reached 55.0% (95% CI 38.7-70.4).

CONCLUSION

The combined detection of the methylation status of SEPT9, SDC2, and ALX4 in plasma holds the potential to further enhance the sensitivity of CRC detection.

DNA Methylation-Based Testing in Peripheral Blood Mononuclear Cells Enables Accurate and Early Detection of Colorectal Cancer

An effective blood-based method for the diagnosis of colorectal cancer has not yet been developed. Molecular alterations of immune cells occur early in tumorigenesis, providing the theoretical underpinning for early cancer diagnosis based on immune cell profiling. Therefore, we aimed to develop an effective detection method based on peripheral blood mononuclear cells (PBMC) to improve the diagnosis of colorectal cancer. Analysis of the genome-wide methylation landscape of PBMCs from patients with colorectal cancer and healthy controls by microarray, pyrosequencing, and targeted bisulfite sequencing revealed five DNA methylation markers for colorectal cancer diagnosis, especially early-stage colorectal cancer. A single-tube multiple methylation-specific quantitative PCR assay (multi-msqPCR) for simultaneous detection of five methylation markers was established, which allowed quantitative analysis of samples with as little as 0.1% PBMC DNA and had better discriminative performance than single-molecule detection. Then, a colorectal cancer diagnostic model (CDM) based on methylation markers and the multi-msqPCR method was constructed that achieved high accuracy for early-stage colorectal cancer (AUC = 0.91; sensitivity = 81.18%; specificity = 89.39%), which was improved compared with CEA (AUC = 0.79). The CDM also enabled a high degree of discrimination for advanced adenoma cases (AUC = 0.85; sensitivity = 63.04%). Follow-up data also demonstrated that the CDM could identify colorectal cancer potential up to 2 years before currently used diagnostic methods. In conclusion, the approach constructed in this study based on PBMC-derived DNA methylation markers and a multi-msqPCR method is a promising and easily implementable diagnostic method for early-stage colorectal cancer.

SIGNIFICANCE

Development of a diagnostic model for early colorectal cancer based on epigenetic analysis of PBMCs supports the utility of altered DNA methylation in immune cells for cancer diagnosis.

Syndecan-2 modulates the YAP pathway in epithelial-to-mesenchymal transition-related migration, invasion, and drug resistance in colorectal cancer

Epithelial-to-mesenchymal transition (EMT) is associated with an invasive phenotype in colorectal cancer (CRC). Here, we examined the roles of YES-associated protein (YAP) and syndecan-2 (SDC2) in EMT-related progression, invasion, metastasis, and drug resistance in CRC. The expression levels of YAP and SDC2 in CRC patient tumor tissue were quantified by PCR and western blotting. EMT-associated characteristics were assessed using Transwell assays and immunohistochemistry. Co-immunoprecipitation, glutathione S-transferase pull-down, and luciferase reporter assays were used to assess interactions between YAP and SDC2. YAP was found to be highly expressed in tumor tissue from 13/16 CRC patients, while SDC2 was highly expressed in the tumor tissue of 12/16 CRC patients. Overexpression of YAP in colon cancer cells led to increased cell viability, invasion, migration, and oxaliplatin resistance demonstrating that YAP plays a role in EMT. In addition, overexpression of YAP led to decreased expression of the large tumor suppressor kinase 1 (LATS1) and mammalian sterile 20-like kinases (MST1/2). Decreased LATS1 expression was associated with increased levels of cell proliferation. Knockdown of YAP by shRNA interference led to decreased cell invasion, migration, and drug resistance in colon cancer cells and reduced tumorigenesis in a mouse xenograft model. Finally, we established that YAP interacted with SDC2, and demonstrated that SDC2 mediated the YAP pathway through the EMT-related factors BMP4, CTGF and FOXM1.

Highly expressed miR-144-3p promotes the proliferation, migration and invasion of colon carcinoma cells by activating the Wnt/β-catenin signaling pathway through targeting SFRP1

Background: To investigate the influence of miR-144-3p on the proliferation, migration and invasion of colon carcinoma by targeting secreted frizzled-related protein 1 (SFRP1) as well as of the Wnt/β-catenin signaling pathway. Methods: Based on the TCGA database, the association between the expression of miR-144-3p and the clinical information and prognosis of patients with colon carcinoma was examined, and SFRP1 was selected as the target gene for further studies based on bioinformatics prediction tools. CCK8 assay, wound healing assay and transwell invasion assay were employed to examine the impact of miR-144-3p on colon carcinoma cells. The regulation of SFRP1 by miR-144-3p was investigated using a dual-luciferase reporter system, and a rescue experiment was conducted to further elucidate whether miR-144-3p promotes the migration of colon carcinoma cells through targeting SFRP1 or not. The Wnt/β-catenin signaling pathway-mediated effect of miR-144-3p in colon carcinoma was finally validated through the targeting of SFRP1. Results: The bioinformatics analysis showed that the miR-144 expression levels were substantially greater in colon carcinoma tissue than in para-carcinoma tissue and were closely with clinical stage and prognosis. The findings obtained from the trial indicated that miR-144-3p substantially expressed in colon carcinoma tissue sample and the colon carcinoma cells, and the overexpressed miR-144-3p boosted the colon carcinoma cells' proliferation, migration and invasion. The results of dual-luciferase reporter gene assay revealed that miR-144-3p targeted SFRP1, and rescue experiment was carried out and its results indicated that miR-144-3p increased colon carcinoma cells' migration through targeting SFRP1. In addition, the molecular axis of miR-144-3p/SFRP1 may over-activate the Wnt/β-catenin signaling pathway. Conclusions: The present study has identified a novel malignant biological behavior, namely the ability of miR-144-3p to enhance the proliferation, migration and invasion of colon carcinoma cells by targeting SFRP1 and activating the Wnt/β-catenin signaling pathway. Consequently, miR-144-3p emerges as a promising diagnostic and therapeutic target for colon carcinoma.

Colorectal cancer detected by liquid biopsy 2 years prior to clinical diagnosis in the HUNT study

BACKGROUND

Colorectal cancer (CRC) is often diagnosed in advanced stages. Circulating tumour DNA (ctDNA) has been proposed as an early diagnostic biomarker. However, as a screening tool, ctDNA has mainly been studied in selected populations at the time of clinical diagnosis. The aim of this study was to detect CRC by known ctDNA markers up to 2 years prior to clinical diagnosis.

METHODS

In this case-control study, methylated ctDNA markers were detected in plasma samples from 106 healthy controls and 106 individuals diagnosed with CRC within 24 months following participation in The Trøndelag Health Study.

RESULTS

The most specific single markers were BMP3, FLI1, IKZF1, SFRP1, SFRP2, NPTX2, SLC8A1 and VIM (specificity >70%). When combining these into a panel, the CRC sensitivity was 43% (95% CI 42.7-43.4) and the CRC specificity was 86% (95% CI 85.7-86.2). The findings were reproduced in an independent validation set of samples.

CONCLUSIONS

Detection of known methylated ctDNA markers of CRC is possible up to 2 years prior to the clinical diagnosis in an unselected population resembling the screening setting. This study supports the hypothesis that some patients could be diagnosed earlier, if ctDNA detection was part of the CRC screening programme.

Colon cancer transcriptome

Over the last four decades, methodological innovations have continuously changed transcriptome profiling. It is now feasible to sequence and quantify the transcriptional outputs of individual cells or thousands of samples using RNA sequencing (RNA-seq). These transcriptomes serve as a connection between cellular behaviors and their underlying molecular mechanisms, such as mutations. This relationship, in the context of cancer, provides a chance to unravel tumor complexity and heterogeneity and uncover novel biomarkers or treatment options. Since colon cancer is one of the most frequent malignancies, its prognosis and diagnosis seem to be critical. The transcriptome technology is developing for an earlier and more accurate diagnosis of cancer which can provide better protectivity and prognostic utility to medical teams and patients. A transcriptome is a whole set of expressed coding and non-coding RNAs in an individual or cell population. The cancer transcriptome includes RNA-based changes. The combined genome and transcriptome of a patient may provide a comprehensive picture of their cancer, and this information is beginning to affect treatment decision-making in real-time. A full assessment of the transcriptome of colon (colorectal) cancer has been assessed in this review paper based on risk factors such as age, obesity, gender, alcohol use, race, and also different stages of cancer, as well as non-coding RNAs like circRNAs, miRNAs, lncRNAs, and siRNAs. Similarly, they have been examined independently in the transcriptome study of colon cancer.

Application and development of noninvasive biomarkers for colorectal cancer screening: a systematic review

BACKGROUND

Colorectal cancer (CRC) is the second most common cause of cancer-related death (9.4% of the 9.9 million cancer deaths). However, CRC develops slowly, and early detection and intervention can effectively improve the survival rate and quality of life. Although colonoscopy can detect and diagnose CRC, it is unsuitable for CRC screening in average-risk populations. Some commercial kits based on DNA mutation or methylation are approved for screening, but the low sensitivity for advanced adenoma or early-stage CRC would limit the applications.

MAIN RESULTS

Recently, researchers have focused on developing noninvasive or minimally invasive, easily accessible biomarkers with higher sensitivity and accuracy for CRC screening. Numerous reports describe advances in biomarkers, including DNA mutations and methylation, mRNA and miRNA, gut microbes, and metabolites, as well as low-throughput multiomics panels. In small cohorts, the specificity and sensitivity improved when fecal immunochemical testing combined with other biomarkers; further verification in large cohorts is expected. In addition, the continuous improvement of laboratory technology has also improved the sensitivity of detection technology, such as PCR, and the application of CRISPR/Cas technology. Besides, artificial intelligence has extensively promoted the mining of biomarkers. Machine learning was performed to construct a diagnosis model for CRC screening based on the cfDNA fragment features from whole-genome sequencing data. In another study, multiomics markers, including cfDNA, epigenetic, and protein signals, were also discovered by machine learning. Finally, advancements in sensor technology promote the applicability of volatile organic compounds in CRC early detection.

CONCLUSION

Here, the authors review advances in early detection and screening of CRC based on different biomarker types. Most studies reported optimistic findings based on preliminary research, and prospective clinical studies are ongoing. These promising biomarkers are expected to more accurately identify early-stage patients with CRC and be applied in the future.

Novel DNA methylation biomarkers in stool and blood for early detection of colorectal cancer and precancerous lesions

BACKGROUND

Early detection and prevention of precancerous lesions can significantly reduce the morbidity and mortality of colorectal cancer (CRC). Here, we developed new candidate CpG site biomarkers for CRC and evaluated the diagnostic value of their expression in blood and stool samples of CRC and precancerous lesions.

METHODS

We analyzed 76 pairs of CRC and adjacent normal tissue samples, 348 stool samples, and 136 blood samples. Candidate biomarkers for CRC were screened using a bioinformatics database and identified using a quantitative methylation-specific PCR method. The methylation levels of the candidate biomarkers were validated using blood and stool samples. The divided stool samples were used to construct and validate a combined diagnostic model and to analyze the independent or combined diagnostic value of candidate biomarkers in stool samples of CRC and precancerous lesions.

RESULTS

Two candidate CpG site biomarkers for CRC, cg13096260 and cg12993163, were identified. Although both biomarkers demonstrated diagnostic performance to a certain extent when using blood samples, they showed better diagnostic value for different stages of CRC and AA with stool samples.

CONCLUSIONS

cg13096260 and cg12993163 detection in stool samples could be a promising approach for screening and early diagnosis of CRC and precancerous lesions.

Circulating Tumor DNA Methylation Biomarkers for Characterization and Determination of the Cancer Origin in Malignant Liver Tumors

Malignant liver tumors include primary malignant liver tumors and liver metastases. They are among the most common malignancies worldwide. The disease has a poor prognosis and poor overall survival, especially with liver metastases. Therefore, early detection and differentiation between malignant liver tumors are critical for patient treatment selection. The detection of cancer and the prediction of its origin is possible with a DNA methylation profile of the tumor DNA compared to that of normal cells, which reflects tissue differentiation and malignant transformation. New technologies enable the characterization of the tumor methylome in circulating tumor DNA (ctDNA), providing a variety of new ctDNA methylation biomarkers, which can provide additional information to clinical decision-making. Our review of the literature provides insight into methylation changes in ctDNA from patients with common malignant liver tumors and can serve as a starting point for further research.

Using Circulating Tumor DNA as a Novel Biomarker to Screen and Diagnose Colorectal Cancer: A Meta-Analysis

(1) Background: Circulating tumor DNA (ctDNA) has emerged as a promising biomarker for many kinds of tumors. However, whether ctDNA could be an accurate diagnostic biomarker in colorectal cancer (CRC) remains to be clarified. The aim of this study was to evaluate the diagnostic accuracy of ctDNA in CRC. (2) Methods: PubMed, Web of Science, and Cochrane databases were searched to identify studies reporting the use of ctDNA to screen and diagnose CRC, and all relevant studies published until October 2022 were enrolled for our analysis. These studies were divided into three primer subgroups: the subgroup of quantitative or qualitative analysis of ctDNA and the subgroup of septin9 (SEPT9) methylation assay. (3) Results: A total of 79 qualified articles with 25,240 subjects were incorporated into our meta-analysis. For quantitative studies, the combined sensitivity (SEN), specificity (SPE), and diagnostic odds ratio (DOR) were 0.723 (95% CI: 0.623-0.803), 0.920 (95% CI: 0.827-0.966), and 23.305 (95% CI: 9.378-57.906), respectively, yielding an AUC of 0.860. The corresponding values for qualitative studies were 0.610 (95% CI: 0.566-0.651), 0.891 (95% CI: 0.878-0.909), 12.569 (95% CI: 9.969-15.848), and 0.823, respectively. Detection of SEPT9 methylation depicted an AUC of 0.879, with an SEN of 0.679 (95% CI: 0.622-0.732), an SPE of 0.903 (95% CI: 0.878-0.923), and a DOR of 20.121 (95% CI:14.404-28.106), respectively. (4) Conclusion: Blood-based ctDNA assay would be a potential novel biomarker for CRC screening and diagnosis. Specifically, quantitative analysis of ctDNA or qualitative analysis of SEPT9 methylation exhibited satisfying diagnostic efficiency. Larger sample studies are needed to further confirm our conclusions and to make the ctDNA approach more sensitive and specific.

Blood-based DNA methylation signatures in cancer: A systematic review

DNA methylation profiles are in dynamic equilibrium via the initiation of methylation, maintenance of methylation and demethylation, which control gene expression and chromosome stability. Changes in DNA methylation patterns play important roles in carcinogenesis and primarily manifests as hypomethylation of the entire genome and the hypermethylation of individual loci. These changes may be reflected in blood-based DNA, which provides a non-invasive means for cancer monitoring. Previous blood-based DNA detection objects primarily included circulating tumor DNA/cell-free DNA (ctDNA/cfDNA), circulating tumor cells (CTCs) and exosomes. Researchers gradually found that methylation changes in peripheral blood mononuclear cells (PBMCs) also reflected the presence of tumors. Blood-based DNA methylation is widely used in early diagnosis, prognosis prediction, dynamic monitoring after treatment and other fields of clinical research on cancer. The reversible methylation of genes also makes them important therapeutic targets. The present paper summarizes the changes in DNA methylation in cancer based on existing research and focuses on the characteristics of the detection objects of blood-based DNA, including ctDNA/cfDNA, CTCs, exosomes and PBMCs, and their application in clinical research.

Analysis of SDC2 gene promoter methylation in whole blood for noninvasive early detection of colorectal cancer

Objectives

Considering the limitations of the current approaches to colorectal cancer (CRC) screening, scientists strived to find noninvasive and more powerful biomarkers for the early diagnosis of CRC. Nowadays, there are different sources of biomarkers for CRC diagnosis. Blood-based samples including circulating cell-free tumor DNA (ctDNA) and DNA extracted from leukocytes in peripheral blood might be promising sources of noninvasive cancer biomarkers such as cancer-specific methylation patterns. In this study, we aimed to evaluate the noninvasive early diagnosis of CRC via quantitative promotor methylation analysis of SDC2 gene in whole blood.

Materials and Methods

Sixty-five CRC patients and 65 healthy participants were enrolled to assess promoter methylation of SDC2 gene in whole blood using the methylation quantification endonuclease-resistant DNA (MethyQESD) technique.

Results

Our findings demonstrated drastic hypermethylation of SDC2 in blood samples from CRC subjects (37.91%) compared with non-malignant individuals (17.02%) (P < 0.001). The sensitivity for detection of CRC by methylation of SDC2 was 81.54%, with a specificity of 69.23%. The ROC curve analysis demonstrated that the AUC was 0.847 (P < 0.001), indicating that the status of SDC2 promoter methylation in whole blood is an excellent biomarker of CRC diagnosis. Furthermore, our results showed that methylation level in CRC patients significantly increased in higher tumor stages, demonstrating that an increased percentage of methylation is correlated with tumor progression (P < 0.001).

Conclusion

SDC2 promoter methylation status in blood samples is a valuable cancer biomarker and holds high power and accuracy in distinguishing CRC patients from healthy subjects in the early stages of the disease.

Clinical Applications of Liquid Biopsy in Colorectal Cancer Screening: Current Challenges and Future Perspectives

Colorectal cancer (CRC) represents the third most prevalent cancer worldwide and a leading cause of mortality among the population of western countries. However, CRC is frequently a preventable malignancy due to various screening tests being available. While failing to obtain real-time data, current screening methods (either endoscopic or stool-based tests) also require disagreeable preparation protocols and tissue sampling through invasive procedures, rendering adherence to CRC screening programs suboptimal. In this context, the necessity for novel, less invasive biomarkers able to identify and assess cancer at an early stage is evident. Liquid biopsy comes as a promising minimally invasive diagnostic tool, able to provide comprehensive information on tumor heterogeneity and dynamics during carcinogenesis. This review focuses on the potential use of circulating tumor cells (CTCs), circulating nucleic acids (CNAs) and extracellular vesicles as emerging liquid biopsy markers with clinical application in the setting of CRC screening. The review also examines the opportunity to implement liquid biopsy analysis during everyday practice and provides highlights on clinical trials researching blood tests designed for early cancer diagnosis. Additionally, the review explores potential applications of liquid biopsies in the era of immunotherapy.

DNA Methylation Biomarkers in Cancer: Current Clinical Utility and Future Perspectives

Epigenetic alterations are related to inherited but reversible changes in modifications that regulate gene activity beyond the DNA sequence. DNA methylation is the best characterized epigenetic modification, controlling DNA stability, DNA structure, transcription, and regulation, contributing to normal development and differentiation. In this section, we first discuss the cellular functions of DNA methylation and focus on how this fundamental biological process is impaired in cancer. Changes in DNA methylation status in cancer have been heralded as promising targets for the development of diagnostic, prognostic, and predictive biomarkers due to their noninvasive accessibility in bodily fluids (such as blood, urine, stool), reversibility, stability, and frequency. The absence of markers for definitive diagnosis of most types of cancer and, in some cases, DNA methylation biomarkers being more specific and sensitive than commonly used protein biomarkers indicate a strong need for continued research to expand DNA methylation markers. Although the information on changes in DNA methylation status in cancer and research on its clinical relevance is rapidly increasing, the number of DNA methylation biomarkers currently available as commercial tests is very small. Here, we focus on the importance of DNA methylation location and target genes likely to be developed in the future for the development of biomarkers in addition to existing commercial tests. Following a detailed study of possible target genes, we summarize the current clinical application status of the most studied and validated DNA methylation biomarkers, including SEPT9, SDC2, BMP3, NDRG4, SFRP2, TFPI2, VIM and MGMT.

RASSF1A methylation as a biomarker for detection of colorectal cancer and hepatocellular carcinoma

BACKGROUND

Studies have validated the potential of methylated cell-free DNA as a biomarker in various tumors, and methylated DNA in plasma may be a potential biomarker for cancer.

AIM

To evaluate the diagnostic value of RASSF1A methylation in plasma for colorectal cancer (CRC) and hepatocellular carcinoma (HCC).

METHODS

A total of 92 CRC patients, 67 colorectal polyp (CRP) patients, 63 HCC patients, and 66 liver cirrhosis (LC) patients were enrolled. The plasma DNA was subjected to DNA extraction, double-strand DNA concentration determination, bisulfite conversion, purification, single-strand DNA concentration determination, and digital polymerase chain reaction (PCR) detection. The methylation rate was calculated. The diagnostic value was evaluated by the area under the curve (AUC).

RESULTS

The age and sex in the CRC and CRP groups and the HCC and LC groups were also matched. The DNA methylation rate of RASSF1A in plasma in the CRC group was 2.87 ± 1.80, and that in the CRP group was 1.50 ± 0.64. DNA methylation of RASSF1A in plasma showed a significant difference between the CRC and CRP groups. The AUC of RASSF1A methylation for discriminating the CRC and CRP groups was 0.82 (0.76-0.88). The AUCs of T1, T2, T3 and T4 CRC and CRP were 0.83 (0.72-0.95), 0.87 (0.78-0.95), 0.86 (0.77-0.95), and 0.75 (0.64-0.85), respectively. The DNA methylation rate of RASSF1A in plasma in the HCC group was 4.45 ± 2.93, and that in the LC group was 2.46 ± 2.07. DNA methylation of RASSF1A in plasma for the HCC and LC groups showed a significant difference. The AUC of RASSF1A methylation for discriminating the HCC and LC groups was 0.70 (0.60-0.79). The AUCs of T1, T2, T3 and T4 HCC and LC were 0.80 (0.61, 1.00), 0.74 (0.59-0.88), 0.60 (0.42-0.79), and 0.68 (0.53-0.82), respectively.

CONCLUSION

RASSF1A methylation in plasma detected by digital PCR may be a potential biomarker for CRC and HCC.

Diagnostic accuracy of DNA-based SDC2 methylation test in colorectal cancer screening: a meta-analysis

Background

A growing body of research suggests that methylated genes can be used as early diagnostic markers for cancer. Some studies on methylated Syndecan 2 (SDC2) have shown that it has a great diagnostic ability in colorectal cancer. This meta-analysis was aimed to estimate the diagnostic performance of methylated SDC2 as a potential novel biomarker to screen for the colorectal cancer.

Methods

Two independent researchers conducted a comprehensive literature search to identify all relevant studies on SDC2 methylation for the diagnosis of colorectal cancer from inception to March 1, 2021. By using STATA and Revman software, the data were analyzed using a Bivariate mixed model. The quality of each study was also evaluated.

Results

A total of 12 studies comprised of 1574 colorectal cancer patients and 1945 healthy people were included in our meta-analysis. Bivariate analysis showed a pooled sensitivity of 0.81 [95% confidence interval (CI) 0.74–0.86], specificity of 0.95 (95% CI 0.93–0.96), positive likelihood ratio of 15.29 (95% CI 10.83–21.60), and negative likelihood ratio of 0.21 (95% CI 0.15–0.27). The diagnostic odds ratio and the area under the summary ROC curve for diagnosing colorectal cancer were 74.42 (95% CI45.44–121.89) and 0.96 (95% CI 0.94–0.97), respectively. For adenomas, the pooled sensitivity and specificity were 0.47 (95% CI 0.34–0.61) and 0.95 (95% CI 0.92–0.97), respectively.

Conclusions

Our analysis revealed that methylated SDC2 could be considered as a potential novel biomarker to screen for colorectal cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02395-7.

DNA Methylation Biomarkers in Colorectal Cancer: Clinical Applications for Precision Medicine

Colorectal cancer (CRC) is the second leading cause of cancer death worldwide that is attributed to gradual long-term accumulation of both genetic and epigenetic changes. To reduce the mortality rate of CRC and to improve treatment efficacy, it will be important to develop accurate noninvasive diagnostic tests for screening, acute, and personalized diagnosis. Epigenetic changes such as DNA methylation play an important role in the development and progression of CRC. Over the last decade, a panel of DNA methylation markers has been reported showing a high accuracy and reproducibility in various semi-invasive or noninvasive biosamples. Research to obtain comprehensive panels of markers allowing a highly sensitive and differentiating diagnosis of CRC is ongoing. Moreover, the epigenetic alterations for cancer therapy, as a precision medicine strategy will increase their therapeutic potential over time. Here, we discuss the current state of DNA methylation-based biomarkers and their impact on CRC diagnosis. We emphasize the need to further identify and stratify methylation-biomarkers and to develop robust and effective detection methods that are applicable for a routine clinical setting of CRC diagnostics particularly at the early stage of the disease.

Epigenetic insights in the diagnosis, prognosis, and treatment selection in CRC, an updated review

BACKGROUND/AIM

The gradual accumulation of genetic and epigenetic alterations can lead to the development of colorectal cancer. In the last decade much research has been done to discover how methylation as an epigenetic alteration leads to carcinogenesis. While Methylation is a biological process, it can influence gene expression by affecting the promoter activity. This article reviews the role of methylation in critical pathways in CRC.

METHODS

In this study using appropriate keywords, all research and review articles related to the role of methylation on different cancers were collected and analyzed. Also, existing information on methylation detection methods and therapeutic sensitivity or resistance due to DNA methylation were reviewed.

RESULTS

The results of this survey revealed that while Methylation is a biological process, it can influence gene expression by affecting the promoter activity. Promoter methylation is associated with up or downregulation of genes involved in critical pathways, including cell cycle, DNA repair, and cell adherence. Hence promoter methylation can be used as a molecular tool for early diagnosis, improving treatment, and predicting treatment resistance.

CONCLUSION

Current knowledge on potential methylation biomarkers for diagnosis and prognoses of CRC has also been discussed. Our survey proposes that a multi-biomarker panel is more efficient than a single biomarker in the early diagnosis of CRC.

The Interaction Between Epigenetic Changes, EMT, and Exosomes in Predicting Metastasis of Colorectal Cancers (CRC)

Worldwide, colorectal cancer (CRC) ranks as the third most common malignancy, and the second most deadly with nearly one million attributable deaths in 2020. Metastatic disease is present in nearly 25% of newly diagnosed CRC, and despite advances in chemotherapy, less than 20% will remain alive at 5 years. Epigenetic change plays a key role in the epithelial-to-mesenchymal transition (EMT), which is a crucial phenotype for metastasis and mainly includes DNA methylation, non-coding RNAs (ncRNAs), and N6-methyladenosine (m6A) RNA, seemingly valuable biomarkers in CRCs. For ncRNAs, there exists a “molecular sponge effect” between long non-coding RNAs (lncRNAs), circular RNAs (circRNAs), and microRNAs (miRNAs). The detection of exosomes is a novel method in CRC monitoring, especially for predicting metastasis. There is a close relationship between exosomes and EMT in CRCs. This review summarizes the close relationship between epigenetic changes and EMT in CRCs and emphasizes the crucial function of exosomes in regulating the EMT process.

Start of an era: circulating cell-free DNA for early detection of cancers

Effective screening modalities are currently available for only a small subset of cancers, and they generally have suboptimal performance with complicated procedures. Therefore, there is an urgent need to develop simple, accurate, and non-invasive methods for early detection of cancers. Genetic and epigenetic alterations in plasma circulating cell-free DNA (cfDNA) have shown the potential to revolutionize methods of early detection of cancers and facilitate subsequent diagnosis to improve survival of patients. The medical interest in cfDNA assays has been inspired by emerging single- and multi-early detection of cancers studies. This review summarizes current technological and clinical advances, in the hopes of providing insights into the development and applications of cfDNA assays in various cancers and clinical scenarios. The key phases of clinical development of biomarkers are highlighted, and the future developments of cfDNA-based liquid biopsies in early detection of cancers are outlined. It is hoped that this study can boost the potential integration of cfDNA-based early detection of cancers into the current clinical workflow.

•

Liquid biopsy, characterized by minimal invasiveness and user friendliness, can identify multiple cancers at the early stage and localize the tissue of origin

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The state-of-the-art technology facilitates the application of circulating cell-free DNA (cfDNA) assays in the early detection of cancers

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cfDNA assays are expected to be integrated into the clinical workflow after technological refinement and clinical trial validation

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The development and application strategies of cfDNA assays in various cancers and clinical scenarios can vary, and the harm-and-benefit should be balanced carefully

A novel method for early detection of colorectal cancer based on detection of methylation of two fragments of syndecan-2 (SDC2) in stool DNA

BACKGROUND

Methylated SDC2 has been proved as a diagnostic marker for human colorectal cancer (CRC), noninvasive stool DNA-based methylation testing also emerges as a novel approach for detecting CRC. The aim of this study was to evaluate the clinical performance of stool DNA-based SDC2 methylation test by a new qPCR detection reagent for early detection of CRC.

METHODS

A new qPCR detection reagent contained two differentially methylated regions in SDC2 CpG islands for the detection of CRC was used in this study. Performance of the SDC2 methylation detection reagent was evaluated by analyzing limit of detection, precision, and specificity. The effect of interfering substances on assay performance was also tested. 339 subjects (102 CRC patients, 50 patients with advanced adenomas, 39 patients with non-advanced adenomas, 18 colitis patients and 130 normal individuals) from the China-Japan Friendship Hospital were evaluated. Approximately 2.5 g of stool sample was collected from each participant. Stool DNA was extracted and bisulfite-converted, followed by qPCR assay, which contained two pairs of primers for the methylation detection of two fragments of the SDC2 gene (named SDC2-A and SDC2-B). The diagnostic value of this test in CRC was evaluated by calculating receiver operating characteristic (ROC) curve, and value of the area under the curve (AUC).

RESULTS

The test kit was able to detect methylated SDC2 in stool DNA samples with concentrations as low as 90 copies/μL in 100% of replicates. The sensitivity for detecting CRC by methylated SDC2-A alone was 85.29% (95% CI 77.03-91.00%) with a specificity of 96.15% (95% CI 91.08-98.58%). The sensitivity by methylated SDC2-B alone was 83.33% (95% CI 74.82-89.42%) with a specificity of 97.69% (95% CI 93.14-99.51%). However, when methylated SDC2-A and methylated SDC2-B were combined, the sensitivity for CRC detection improved to 87.25% (95% CI 79.27-92.53%) with a specificity of 94.62% (95% CI 89.11-97.56%). Further, the detection reagent achieved ROC-AUC 0.874 (95% CI 0.822-0.927) for SDC2-A, 0.906 (95% CI 0.859-0.952) for SDC2-B, and 0.939 (95% CI 0.902-0.977) for SDC2-Combine A&B.

CONCLUSIONS

This study validated the capability of stool DNA-based SDC2 methylation test for early screening of CRC, and combined detection of two fragments of SDC2 gene could improve detection sensitivity.

Advances in tests for colorectal cancer screening and diagnosis

INTRODUCTION

Colorectal cancer (CRC) is the second leading cause of cancer-related deaths globally. Nonetheless, with early detection of CRC or its precancerous lesions, mortality, and CRC incidence can be reduced. Although colonoscopy is currently the gold standard for CRC screening and diagnosis, its invasive nature, and troublesome bowel preparation deter patient participation. Therefore, there is a need to expand the use of noninvasive or minimally invasive methods to increase patient compliance.

AREAS COVERED

This review summarizes advances in different methods for CRC screening, including stool bacterial and metagenomic markers, fecal proteins, genetic and epigenetic markers in blood and stools, and imaging modalities. The cost-effectiveness of these methods is also discussed. FIT is more cost-effective compared to virtual colonoscopy, mSEPT9 test, and Multitarget Stool DNA test, while the cost-effectiveness of other noninvasive methods requires further evaluation.

EXPERT OPINION

Recent evidence has well demonstrated the usefulness of gut microbiome and certain fecal bacterial markers in the noninvasive diagnosis of CRC and its precancerous lesions. Many of the fecal biomarkers, from host cells or the gut environment, show better diagnostic sensitivity than FIT. New screening tests based on these fecal biomarkers can be expected to replace FIT with higher cost-effectiveness in the near future.

A Liquid Biopsy-Based Approach for Monitoring Treatment Response in Post-Operative Colorectal Cancer Patients

Monitoring the therapeutic response of colorectal cancer (CRC) patients is crucial to determine treatment strategies; therefore, we constructed a liquid biopsy-based approach for tracking tumor dynamics in non-metastatic (nmCRC) and metastatic (mCRC) patients (n = 55). Serial blood collections were performed during chemotherapy for measuring the amount and the global methylation pattern of cell-free DNA (cfDNA), the promoter methylation of SFRP2 and SDC2 genes, and the plasma homocysteine level. The average cfDNA amount was higher (p < 0.05) in nmCRC patients with recurrent cancer (30.4 ± 17.6 ng) and mCRC patients with progressive disease (PD) (44.3 ± 34.5 ng) compared to individuals with remission (13.2 ± 10.0 ng) or stable disease (12.5 ± 3.4 ng). More than 10% elevation of cfDNA from first to last sample collection was detected in all recurrent cases and 92% of PD patients, while a decrease was observed in most patients with remission. Global methylation level changes indicated a decline (75.5 ± 3.4% vs. 68.2 ± 8.4%), while the promoter methylation of SFRP2 and SDC2 and homocysteine level (10.9 ± 3.4 µmol/L vs. 13.7 ± 4.3 µmol/L) presented an increase in PD patients. In contrast, we found exact opposite changes in remission cases. Our study offers a more precise blood-based approach to monitor the treatment response to different chemotherapies than the currently used markers.

DNA methylation-based diagnostic, prognostic, and predictive biomarkers in colorectal cancer

DNA methylation is an epigenetic mechanism regulating gene expression. Changes in DNA methylation were suggested to be useful biomarkers for diagnosis, and for the determination of prognosis and treatment response. Here, we provide an overview of methylation-based biomarkers in colorectal cancer. First, we start with the two methylation-based diagnostic biomarkers already approved for colorectal cancer, SEPT9 and the combination of NDRG4 and BMP3. Then, we provide a list-based overview of new biomarker candidates depending on the sample source including plasma, stool, urine, and surgically removed tumor tissues. The most often identified markers like SDC2, VIM, APC, MGMT, SFRP1, SFRP2, and NDRG4 have distinct functions previously linked to tumor progression. Although numerous studies have identified tumor-specific methylation changes, most of these alterations were observed in a single study only. The lack of validation in independent samples means low reproducibility and is a major limitation. The genome-wide determination of methylation status (methylome) can provide data to solve these issues. In the third section of the review, methylome studies focusing on different aspects related to CRC, including precancerous lesions, CRC-specific changes, molecular subtypes, aging, and chemotherapy response are summarized. Notably, techniques simultaneously analyzing a large set of regions can also uncover epigenetic regulation of genes which have not yet been associated with tumorigenesis previously. A remaining constraint of studies published to date is the low patient number utilized in these preventing the identification of clinically valuable biomarker candidates. Either future large-scale studies or the integration of already available methylome-level data will be necessary to uncover biomarkers sufficiently robust for clinical application.

IL-6 Promoter Hypomethylation Acts As a Diagnostic Biomarker in Hepatitis B Virus-Associated Hepatocellular Carcinoma

BACKGROUND

New biomarkers are needed to detect hepatocellular carcinoma at an earlier stage and to individualize treatment strategies. IL-6 has been proven to be associated with liver cancer in numerous studies.

AIM

To evaluate the value of the IL-6 promoter methylation level as a noninvasive biomarker for the diagnosis of liver cancer.

METHODS

A retrospective analysis of 165 patients with HBV-associated hepatocellular carcinoma (HCC), 198 patients with chronic hepatitis B (CHB) and 31 healthy controls were involved. The methylight was detected the methylation level of the IL-6 promoter in peripheral blood mononuclear cells (PBMCs), clinical and laboratory parameters were obtained.

RESULTS

IL-6 promoter methylation levels were significantly lower in patients with HCC (median 53.59%, interquartile range 52.01-54.75%) than in those with CHB (median 56.05%, interquartile range 54.65-57.67%; P<0.001). The level of IL-6 mRNA in patients with HCC (median 0.371, interquartile range 0.173-0.671) was significantly higher than that in patients with CHB (median 0.203, interquartile range 0.108-0.354; P<0.001) and HCs (median 0.189, interquartile range 0.140-0.262; P=0.001). Meanwhile, the PMR value of IL-6 was notably negatively correlated with the mRNA expression level (Spearman's R=-0.201, P<0.001). The IL-6 PMR value of HCC patients in age (Spearman's R=0.193, P=0.026) and TBIL (Spearman's R=0.186, P=0.032) were very weak correlated. At the same time, the level of IL-6 promoter methylation was also an independent factor in the development of liver cancer. When the IL-6 promoter methylation level was used to diagnose HCC, its detective value was superior to AFP [area under the receiver operating characteristic curve (AUC) 0.773 vs. 0.686, P=0.027], And the combined use of AFP and IL-6 methylation level can improve the area under the receiver operating characteristic curve (p=0.011).

CONCLUSION

IL-6 promoter hypomethylation is present in hepatocellular carcinoma, and it may be used as a noninvasive biomarker to detect early liver cancer.

Methylation of SDC2/TFPI2 and Its Diagnostic Value in Colorectal Tumorous Lesions

Background:SDC2 methylation is a feasible biomarker for colorectal cancer detection. Its specificity for colorectal cancer is higher than 90%, but the sensitivity is normally lower than 90%. This study aims to improve the sensitivity of SDC2 detection through finding a high positive target from the false-negative samples of SDC2 detection based on analysis of the bowel subsite difference in methylation.

Methods: Hypermethylated TFPI2 was identified in SDC2 hypomethylated colorectal cancer samples retrieved from TCGA database with the methylation level lower than 0.2. The methylation-specific PCR assay was developed and then evaluated using tissue samples (184 cancer and 54 healthy control samples) and stool samples (289 cancer, 190 adenoma, and 217 healthy control samples).

Results:TFPI2 was hypermethylated in most SDC2 hypomethylated colorectal cancer samples. When the SDC2/TFPI2-combined PCR assay was performed in stool specimens, the AUC value of cancer vs. control was 0.98, with the specificity of 96.40% and sensitivity of 96.60%, and the AUC value of adenoma vs. control was 0.87, with the specificity of 95.70% and the sensitivity of 80.00%. The improvement in sensitivity was the most momentous in the left colon. As the detection index, the Ct value was better in improving the sensitivity of detection than the methylation level based on the 2^−ΔΔCt value.

Conclusion:TFPI2 can improve the sensitivity of SDC2 methylation–specific detection of colorectal tumorous lesions while maintaining high specificity, in particular reducing the missed detection of left colon cancer and adenoma.

Comparison of performance of two Stool DNA Tests and a Faecal Immunochemical Test in Detecting Colorectal Neoplasm: a Multicentre Diagnostic Study

BACKGROUND

The most widely used non-invasive screening tests for colorectal cancer (CRC) are faecal occult blood tests. Stool DNA test was developed in recent years. However, direct comparative analyses of these tests within the same population are still sparse.

METHODS

2842 participants who visited outpatient clinics or cancer screening centres were enrolled. Stool DNA test-I (KRAS, BMP3, NDRG4, and haemoglobin immunochemical tests), stool DNA test-II (SDC2 and SFRP2 tests) and FIT alone were performed and colonoscopy was used as the gold standard among 2240 participants. 42 and 302 participants had CRC and advanced adenomas (AA), respectively.

RESULTS

The sensitivity for CRC of stool DNA test-I, -II and FIT was 90.5%, 92.9% and 81.0%, respectively. The sensitivity for advanced neoplasm (CRC plus AA) of stool DNA test-I, -II and FIT was 34.9%, 42.2% and 25.9%, respectively. The specificity of stool DNA test-I, -II and FIT was 91.4%, 93.3% and 96.8%, respectively, among those with negative results on colonoscopy. When the specificity of FIT was adjusted to match that of stool DNA tests by changing the threshold, no significant difference was seen in the sensitivities among the 3 tests for detecting CRC. For advanced neoplasm, the sensitivity of FIT was higher than DNA test-I and similar to DNA test-II under the same specificities.

CONCLUSIONS

There was no significant advantage of the two stool DNA tests compared to FIT in detecting CRC or advanced neoplasm in this study.

IMPACT

Our findings do not support extensive use of stool DNA tests instead of FIT.

Combined detection of stool-based methylation indicators for early screening of colorectal neoplasm

In the past two decades, several methylated DNA targets, including gene promoters and other intronic markers have been explored in tumors and benign lesions. Therefore, it can be expected that a panel of stool-based biomarkers will become a screening method for colorectal cancer (CRC) and adenoma with better sensitivity and specificity, aiming to decrease the incidence and mortality of CRC. In this study, the methylation of secreted frizzled-related protein 1 (SFRP1), hyperplastic polyposis protein 1 (HPP1), α-internexin (INA), Wnt inhibitory factor 1 (WIF1), tissue factor pathway inhibitor 2 (TFPI2), ikaros family zinc finger protein 1 (IKZF1), and spastic paraplegia 20 (SPG20) were detected in stool samples from patients with CRC, adenoma, polyps, and healthy controls, respectively, and these biomarkers were used to establish a logistic regression model for classification. Receiver operating characteristic (ROC) curves were drawn to assess the importance of each biomarker. Subsequently, a biomarker or combination of biomarkers was analyzed for early screening of high-risk neoplasm. The data showed that when a single biomarker was used for CRC screening, the sensitivity ranged from 63.9% to 76.8%, the area under the curve (AUC) ranged from 0.821 to 0.875, and the accuracy ranged from 77.0% to 84.5%. Finally, the methylation of SFRP1, HPP1, TFPI2, and IKZF1 was selected using a backward stepwise method in the multivariate logistic analysis according to the Akaike Information Criterion. These findings indicate that stool DNA biomarkers have good diagnostic power in discriminating high-risk level of neoplasm from healthy population.

Multiple Biomarker-Combined Screening for Colorectal Cancer Based on Bisulfate Conversion-Free Detection of Fecal DNA Methylation

To evaluate the applicability of bisulfate conversion-free methylation assay based on enzyme digestion in fecal screening for colorectal cancer (CRC). Stool samples were collected from a total of 1142 participants with intestinal abnormalities, including 180 positive cases, 60 advanced adenomas, and 902 negative cases. DNA from reference cell lines and clinical samples was extracted and digested with an enzyme to detect the methylation of CRC markers SEPT9, SDC2, NDRG4, SFRP2, and BMP3 genes. Statistical analysis was then used to determine the ability of the markers, both individually and in combination, to detect CRC and adenoma. Our results showed that the enzyme digestion method could suitably detect DNA marker methylation in as low as 1% of the cell lines. BMP3 had a considerably low detection rate in all clinical samples, with only 6 positive cases detected out of 180 cancer samples. Our findings showed that the combination of SEPT9, SDC2, and SFRP2 had an area under the receiver operation curve of 0.937, sensitivity of 94.11%, and specificity of 89.21% for detecting CRC. Moreover, the detection sensitivity of adenoma can also reach 38.33%. After innovatively utilizing bisulfate conversion-free methylation assay for CRC screening, this study verified the potential clinical applicability of combining multiple biomarkers for CRC screening in a large number of samples.

Promising Epigenetic Biomarkers for the Early Detection of Colorectal Cancer: A Systematic Review

In CRC, screening compliance is decreased due to the experienced discomfort associated with colonoscopy, although this method is the gold standard in terms of sensitivity and specificity. Promoter DNA methylation (hypomethylation or hypermethylation) has been linked to all CRC stages. Study objectives: to systematically review the current knowledge on approved biomarkers, reveal new potential ones, and inspect tactics that can improve performance. This research was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines; the risk of bias was evaluated using the revised Quality Assessment of Diagnostic Accuracy Studies criteria (QUADAS-2). The Web of Science® Core Collection, MEDLINE® and Scopus® databases were searched for original articles published in peer-reviewed journals with the specific keywords "colorectal cancer", "early detection", "early-stage colorectal cancer", "epigenetics", "biomarkers", "DNA methylation biomarkers", "stool or blood or tissue or biopsy", "NDRG4", "BMP3", "SEPT9", and "SDC2". Based on eligibility criteria, 74 articles were accepted for analysis. mSDC2 and mSEPT9 were frequently assessed in studies, alone or together as part of the ColoDefense panel test-the latter with the greatest performance. mBMP3 may not be an appropriate marker for detecting CRC. A panel of five methylated binding sites of the CTCF gene holds the promise for early-stage specific detection of CRC. CRC screening compliance and accuracy can be enhanced by employing a stool mt-DNA methylation test.

Risk-Predictive and Diagnostic Biomarkers for Colorectal Cancer; a Systematic Review of Studies Using Pre-Diagnostic Blood Samples Collected in Prospective Cohorts and Screening Settings

This systematic review summarizes the evidence for blood-based colorectal cancer biomarkers from studies conducted in pre-diagnostic, asymptomatic settings. Of 1372 studies initially identified, the final selection included 30 studies from prospective cohorts and 23 studies from general screening settings. Overall, the investigations had high quality but considerable variability in data analysis and presentation of results, and few biomarkers demonstrated a clinically relevant discriminatory ability. One of the most promising biomarkers was the anti-p53 antibody, with consistent findings in one screening cohort and in the 3-4 years prior to diagnosis in two prospective cohort studies. Proteins were the most common type of biomarker assessed, particularly carcinoembryonic antigen (CEA) and C-reactive protein (CRP), with modest results. Other potentially promising biomarkers included proteins, such as AREG, MIC-1/GDF15, LRG1 and FGF-21, metabolites and/or metabolite profiles, non-coding RNAs and DNA methylation, as well as re-purposed routine lab tests, such as ferritin and the triglyceride-glucose index. Biomarker panels generally achieved higher discriminatory performance than single markers. In conclusion, this systematic review highlighted anti-p53 antibodies as a promising blood-based biomarker for use in colorectal cancer screening panels, together with other specific proteins. It also underscores the need for validation of promising biomarkers in independent pre-diagnostic settings.

Prognostic targets recognition of rectal adenocarcinoma based on transcriptomics

Colorectal cancer is currently the third most common cancer around the world. In this study, we chose a bioinformatics analysis method based on network analysis to dig out the pathological mechanism and key prognostic targets of rectal adenocarcinoma (READ).In this study, we downloaded the clinical information data and transcriptome data from the Cancer Genome Atlas database. Differentially expressed genes analysis was used to identify the differential expressed genes in READ. Community discovery algorithm analysis and Correlation analysis between gene modules and clinical data were performed to mine the key modules related to tumor proliferation, metastasis, and invasion. Genetic significance (GS) analysis and PageRank algorithm analysis were applied for find key genes in the key module. Finally, the importance of these genes was confirmed by survival analysis.Transcriptome datasets of 165 cancer tissue samples and 9 paracancerous tissue samples were selected. Gene coexpression networks were constructed, multilevel algorithm was used to divide the gene coexpression network into 11 modules. From GO enrichment analysis, module 11 significantly associated with clinical characteristic N, T, and event, mainly involved in 2 types of biological processes which were highly related to tumor metastasis, invasion, and tumor microenvironment regulation: cell development and differentiation; the development of vascular and nervous systems. Based on the results of survival analysis, 7 key genes were found negatively correlated to the survival rate of READ, such as MMP14, SDC2, LAMC1, ELN, ACTA2, ZNF532, and CYBRD1.Our study found that these key genes were predicted playing an important role in tumor invasion and metastasis, and being associated with the prognosis of READ. This may provide some new potential therapeutic targets and thoughts for the prognosis of READ.

DNA methylation detection technology and plasma-based methylation biomarkers in screening of gastrointestinal carcinoma

DNA methylation is of paramount importance for the evolution of human cancers. Its high sensitivity and specificity make it a potential biomarker for early cancer screening in the context of an increasing global burden of gastrointestinal (GI) carcinoma. More DNA methylation biomarkers are emerging with the development of liquid biopsy and sensitive DNA methylation detection technology. This review provides an overview of DNA methylation, focusing on the presentation and comparison of 5-methylcytosine detection technologies, and introduces the promising plasma-based cell-free DNA (cfDNA) methylation biomarkers published in recent years for early screening of GI carcinoma. Finally, we summarize and discuss the future of plasma cfDNA methylation markers detection as a clinical tool for early screening of GI carcinoma.

Advances in Early Detection of Colorectal Cancer: A Focus on Non-invasive Biomarkers

BACKGROUND

Colorectal cancer (CRC) is the third most commonly diagnosed cancer worldwide. Currently, colonoscopy remains the gold standard diagnostic test for CRC detection. Nonetheless, this technique is invasive and expensive. Remarkable ongoing strategies are focusing on the development of affordable methods to diagnose CRC at earlier stages. The introduction of suitable noninvasive, sensitive and specified diagnostic tests for early CRC detection by employing biomarker analysis seems to be a fundamental need to reduce the numbers of unnecessary colonoscopies. In this review, we provide an overview of single- and multi-panel biomarkers (Genomic markers, transcriptome markers, proteomic markers, inflammatory markers, and microbiome markers) encompassing noninvasive tests in blood and stool for early CRC detection.

METHODS

A bibliographic search using PubMed/Medline, Web of Science, and EBSCOhost databases was performed to find relevant published studies over the last 6 years. Forty-three pertinent studies were included in this review.

RESULTS

The primary outcome highlights the sensitivity and specificity of single diagnostic biomarkers studied in blood or stool. The secondary outcome reveals the sensitivity and specificity of the biomarkers panel (combinations) in blood or stool. While some markers show better performance, others are not suitable for screening purposes.

CONCLUSION

There is a need to adjust experimental and analytical tests that can interfere with a robust result to replace or supplement those markers that are currently in use. Nevertheless, robust verification and validation with large clinical cohorts are needed for successful noninvasive tests that can fulfill the role of colonoscopy.

Methylated circulating tumor DNA as a biomarker for colorectal cancer diagnosis, prognosis, and prediction

Worldwide, colorectal cancer (CRC) is a deadly disease whose death rate ranks second among cancers though its incidence ranks third. Early CRC detection is key and is associated with improved survival outcomes. However, existing tests for CRC diagnosis have several weaknesses thus rendering them inefficient. Moreover, reliable prognostic tests that can predict the overall cancer outcome and recurrence of the disease as well as predictive markers that can assess effectiveness of therapy are still lacking. Thus, shifting to noninvasive liquid biopsy or blood-based biomarkers is vital to improving CRC diagnosis, prognosis, and prediction. Methylated circulating tumor DNA (ctDNA) has gained increased attention as a type of liquid biopsy that is tumor-derived fragmented DNA with epigenetic alterations. Methylated ctDNA are more consistently present in blood of cancer patients as compared to mutated ctDNA. Hence, methylated ctDNA serves as a potential biomarker for CRC that is worth investigating. In this review, we explore what has been reported about methylated ctDNA as a biomarker for CRC diagnosis that can distinguish between CRC patients or those having adenoma and healthy controls as validated specifically through ROC curves. We also examine methylated ctDNA as a biomarker for CRC prognosis and prediction as confirmed through robust statistical analyses. Finally, we discuss the major technical challenges that limits the use of methylated ctDNA for clinical application and suggest possible recommendations to enhance its usage.