Stool Investigations for Colorectal Cancer Screening: From Occult Blood Test to DNA Analysis

Non-steroidal anti-inflammatory drugs and biomarkers: A new paradigm in colorectal cancer

Colorectal cancer is a sporadic, hereditary, or familial based disease in its origin, caused due to diverse set of mutations in large intestinal epithelial cells. Colorectal cancer (CRC) is a common and deadly disease that accounts for the 4^th worldwide highly variable malignancy. For the early detection of CRC, the most common predictive biomarker found endogenously are KRAS and ctDNA/cfDNA along with SEPT9 methylated DNA. Early detection and screening for CRC are necessary and multiple methods can be employed to screen and perform early diagnosis of CRC. Colonoscopy, an invasive method is most prevalent for diagnosing CRC or confirming the positive result as compared to other screening methods whereas several non-invasive techniques such as molecular analysis of breath, urine, blood, and stool can also be performed for early detection. Interestingly, widely used medicines known as non-steroidal anti-inflammatory drugs (NSAIDs) to reduce pain and inflammation have reported chemopreventive impact on gastrointestinal malignancies, especially CRC in several epidemiological and preclinical types of research. NSAID acts by inhibiting two cyclooxygenase enzymes, thereby preventing the synthesis of prostaglandins (PGs) and causing NSAID-induced apoptosis and growth inhibition in CRC cells. This review paper majorly focuses on the diversity of natural and synthetic biomarkers and various techniques for the early detection of CRC. An approach toward current advancement in CRC detection techniques and the role of NSAIDs in CRC chemoprevention has been explored systematically. Several prominent governing mechanisms of the anti-cancer effects of NSAIDs and their synergistic effect with statins for an effective chemopreventive measure have also been discussed in this review paper.

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.

Expression profiles of miR-196, miR-132, miR-146a, and miR-134 in human colorectal cancer tissues in accordance with their clinical significance : Comparison regarding KRAS mutation

BACKGROUND

Colorectal cancer (CRC) is among the most widespread malignancies in the world. MicroRNA (miRNA) has been identified as an important modulator of the biological processes of the cells. This group of noncoding RNAs also has a pivotal function in the growth and development of human cancers, including CRC. Among these miRNAs, miR-196, miR-132, miR-146a, and miR-134 have fundamental impacts on the regulation of cancers. The current study aimed to investigate the involvement of these miRNAs in CRC patients.

METHODS

In this study, 50 pairs of tumor and tumor margin samples of CRC patients were investigated to assess the expression levels of miR-196, miR-132, miR-146a, and miR-134 in this cancer. For this purpose, firstly, quantitative real-time PCR (qRT-PCR) was applied. Also, KRAS mutation and clinicopathological characteristics of the CRC patients were analyzed in the study groups.

RESULTS

The findings demonstrated the overexpression of miR-196 (P-value = 0.0045) and miR-146a (P-value = 0.0033) in tumor tissues compared to controls. Conversely, the expression levels of miR-132 (P-value = 0.00032) and miR-134 (P-value < 0.0001) were downregulated in tumor tissues. Also, miR-146a was the only miRNA with significant expression change in the case of the KRAS gene mutation. Interestingly, the expression ratio of these miRNAs was significantly associated with some of the clinicopathological features of the patients, such as lymph node and distant metastases.

CONCLUSION

Our data demonstrated that these miRNAs appear to be promising novel biomarkers for early diagnosis of CRC and may pave the way for the future establishment of novel therapeutic options for CRC.

Ethnic disparities in the uptake of colorectal cancer screening: An analysis of the West London population

AIM

Colorectal cancer (CRC) screening reduces mortality but variation exists in uptake, with poorer uptake in ethnic minority groups. The aim of this work was to evaluate the relationship between ethnicity and uptake of CRC screening in West London.

METHOD

Results of CRC screening from the Central London, West London, Hammersmith and Fulham, Hounslow and Ealing Clinical commissioning group collaborative between 2012 and 2017 were retrospectively analysed. These five clinical commissioning groups (CCGs) are located in West London. Compliance with screening according to ethnic group was evaluated compared with White British as the control.

RESULTS

A total of 155 038 individuals were screened. White British individuals had the highest compliance (52.6%). A maximum difference in compliance of 8.2% was seen between CCGs. The odds of being less likely to participate were significant (p < 0.05) in all ethnic minorities except for Asian Chinese on univariate and multivariate analysis (adjusted OR 1.091, p = 0.88).

CONCLUSION

This is the largest retrospective study focusing on the role of ethnicity in the uptake of CRC screening in England. Poor uptake of screening in all ethnic minorities in West London, with the exception of Asian Chinese individuals in particular, is a novel finding. A mandate to routinely collect ethnicity data, the use of a single more diverse census and further intervention are needed to understand this disparity and reduce health inequity.

N-MYC Downstream Regulated Gene 4 (NDRG4), a Frequent Downregulated Gene through DNA Hypermethylation, plays a Tumor Suppressive Role in Esophageal Adenocarcinoma

Simple Summary

Esophageal adenocarcinoma has become a major clinical challenge in the western world due to its rapid increasing incidence and poor overall prognosis. Understanding the molecular events of its tumorigenesis is the key to better diagnosis and development of better therapeutic strategies. In the current study we aimed to identify epigenetic alteration targets in esophageal adenocarcinoma. We focused on a candidate gene, NDRG4 (N-myc downregulated gene 4). We found that NDRG4 was frequent downregulated in esophageal adenocarcinoma through DNA hypermethylation of its promoter region. Re-expression of NRDG4 in cancer cells significantly suppressed tumor growth via inhibition of cell proliferation. These results will improve our understanding on how dysfunction of NDRG4 contributes to esophageal adenocarcinoma. DNA hypermethylation of NDRG4 may be a useful biomarker in clinical monitoring of esophageal adenocarcinoma patients.

Abstract

The incidence of esophageal adenocarcinoma (EAC) has been rising dramatically in the past few decades in the United States and Western world. The N-myc downregulated gene 4 (NDRG4) belongs to the human NDRG family. In this study, we aimed to identify the expression levels, regulation, and functions of NDRG4 in EAC. Using an integrative epigenetic approach, we identified genes showing significant downregulation in EAC and displaying upregulation after 5-Aza-deoxycitidine. Among these genes, likely to be regulated by DNA methylation, NDRG4 was among the top 10 candidate genes. Analyses of TCGA (The Cancer Genome Atlas) and GEO (Gene Expression Omnibus) data sets and EAC tissue samples demonstrated that NDRG4 was significantly downregulated in EAC (p < 0.05). Using Pyrosequencing technology for quantification of DNA methylation, we detected that NDRG4 promoter methylation level was significantly higher in EAC tissue samples, as compared to normal esophagus samples (p < 0.01). A strong inverse correlation between NDRG4 methylation and its gene expression levels (r = −0.4, p < 0.01) was observed. Treatment with 5-Aza restored the NDRG4 expression, confirming that hypermethylation is a driving force for NDRG4 silencing in EAC. Pathway and gene set enrichment analyses of TCGA data suggested that NDRG4 is strongly associated with genes related to cell cycle regulation. Western blotting analysis showed significant downregulation of Cyclin D1, CDK4 and CDK6 in EAC cells after overexpression of NDRG4. Functionally, we found that the reconstitution of NDRG4 resulted in a significant reduction in tumor cell growth in two-dimensional (2D) and three-dimensional (3D) organotypic culture models and inhibited tumor cell proliferation as indicated by the EdU (5-ethynyl-2′-deoxyuridine) proliferation assay.

Fecal MicroRNAs as Potential Biomarkers for Screening and Diagnosis of Intestinal Diseases

MicroRNAs (miRNAs) are a class of conserved endogenous, small non-coding RNA molecules with a length of 18–25 nucleotides that regulate gene expression by RNA interference processes, including mRNA chopping, mRNA deadenylation, and translation inhibition. miRNAs maintain the physiological functions of the intestine and are instrumental in gut pathogenesis. miRNAs play an important role in intercellular communication and are present in all body fluids, including stools with different composition and concentrations. However, under diseased conditions, miRNAs are aberrantly expressed and act as negative regulators of gene expression. The stable and differentially expressed miRNAs in stool enables miRNAs to be used as potential biomarkers for screening of various intestinal diseases. In this review, we summarize the expressed miRNA profile in stool and highlight miRNAs as biomarkers with potential clinical and diagnostic applications, and we aim to address the prospects for recent advanced techniques for screening miRNA in diagnosis and prognosis of intestinal disorders.

Multitarget stool DNA test compared with fecal occult blood test for colorectal cancer screening

Patient screening is important for early diagnosis of colorectal cancer (CRC). The present study aimed to compare the multitarget stool DNA (mt-sDNA) test with the fecal occult blood test (FOBT) for CRC screening. A total of 151 individuals were screened using colonoscopy, mt-sDNA and FOBT for the detection of CRC and adenoma. The results of the mt-sDNA test and FOBT were compared with colonoscopy to examine their sensitivity and specificity. Subsequently, the sensitivity and specificity of the mt-sDNA test were compared with those of FOBT in CRC and large adenoma. Stool samples were collected from patients with CRC (n=50) or large adenoma (n=51), as well as from normal controls (n=50). The mt-sDNA test outperformed FOBT in detecting CRC with a sensitivity of 90.0% (45/50) vs. 42.0% (21/50), advanced adenoma with a sensitivity of 70.6% (36/51) vs. 19.6% (10/51), stage I–III CRC with a sensitivity of 91.9% (34/37) vs. 29.7% (11/37), and stage IV CRC with a sensitivity of 84.6% (11/13) vs. 76.9% (10/13). In addition, the mt-sDNA test exhibited a specificity of 94.0% (47/50) in detecting CRC, which was superior to FOBT with a specificity of 90.0% (45/50). Therefore, the mt-sDNA test may have higher sensitivity and specificity compared with FOBT in diagnosing both CRC and advanced adenoma.

Risk stratification of symptomatic patients suspected of colorectal cancer using faecal and urinary markers

AIM

Faecal markers, such as the faecal immunochemical test for haemoglobin (FIT) and faecal calprotectin (FCP), have been increasingly used to exclude colorectal cancer (CRC) and colonic inflammation. However, in those with lower gastrointestinal symptoms there are considerable numbers who have cancer but have a negative FIT test (i.e. false negative), which has impeded its use in clinical practice. We undertook a study of diagnostic accuracy CRC using FIT, FCP and urinary volatile organic compounds (VOCs) in patients with lower gastrointestinal symptoms.

METHOD

One thousand and sixteen symptomatic patients with suspected CRC referred by family physicians were recruited prospectively in accordance with national referring protocol. A total of 562 patients who completed colonic investigations, in addition to providing stool for FIT and FCP as well as urine samples for urinary VOC measurements, were included in the final outcome measures.

RESULTS

The sensitivity and specificity for CRC using FIT was 0.80 [95% confidence interval (CI) 0.66-0.93] and 0.93 (CI 0.91-0.95), respectively. For urinary VOCs, the sensitivity and specificity for CRC was 0.63 (CI 0.46-0.79) and 0.63 (CI 0.59-0.67), respectively. However, for those who were FIT-negative CRC (i.e. false negatives), the addition of urinary VOCs resulted in a sensitivity of 0.97 (CI 0.90-1.0) and specificity of 0.72 (CI 0.68-0.76).

CONCLUSIONS

When applied to the FIT-negative group, urinary VOCs improve CRC detection (sensitivity rises from 0.80 to 0.97), thus showing promise as a second-stage test to complement FIT in the detection of CRC.

Chemoprevention of inflammation-related colorectal cancer by silymarin-, acetyl-11-keto-beta-boswellic acid-, curcumin- and maltodextrin-enriched dietetic formulation in animal model

On the basis of preliminary in vitro experience, we assessed whether an enriched nutritional formulation with estrogen receptor (ER)-beta agonist and anti-inflammatory properties may prevent inflammation-associated colorectal cancer (CRC) in an animal model. Study sample enclosed 110 C57BL/6J male mice. Forty underwent dietary supplement safety assessment (20 standard diet and 20 enriched formulation). Seventy were treated with azoxymethane (AOM)/dextran sulfate sodium and divided into two groups: 35 received standard diet and 35 enriched formulation (curcumin, boswellic acids, silymarin and maltodextrins). Miniature colonoscopy demonstrated colitis and solid lesion development in five mice/group 100 days after first AOM injection. Mice were killed after 10 days. In each group, four subgroups received intraperitoneal bromodeoxyuridine (BrdU) injection at 24th/48th/72nd/96th hour before killing. Anti-inflammatory effect and chemoprevention were evaluated by lesion number/size, histological inflammation/dysplasia/neoplasia assessment, pro-inflammatory cytokine messenger RNA (mRNA), ER-beta/ER-alpha/BrdU immunohistochemistry and TUNEL immunofluorescence. Standard formulation assumption was associated with colon shortening compared with enriched one (P = 0.04), which reduced solid lesion number and size (P < 0.001 for both), histological inflammation score (P = 0.04), pro-inflammatory cytokine mRNA expression (P < 0.001), number of low-grade dysplasia (LGD; P = 0.03) and high-grade dysplasia (P < 0.001) areas. CRC was observed in 69.6% in standard and 23.5% in enriched formulation assuming animals (P < 0.001). Enriched formulation induced lower ER-alpha expression in CRC (P < 0.001) and higher ER-beta expression in LGD (P < 0.001) being associated to higher epithelial turnover (BrdU; P<0.001) in normal mucosa and increased apoptosis in LGD and CRC (P < 0.001 for both). Our results are promising for a successful anti-inflammatory and chemopreventive effect of enriched formulation in CRC arising from inflamed tissue.

Cost-effectiveness of Colorectal Cancer Screening and Treatment Methods: Mapping of Systematic Reviews

OBJECTIVE

Due to extensive literature on colorectal cancer and their heterogeneous results, this study aimed to summarize the systematic reviews which review the cost-effectiveness studies on different aspects of colorectal cancer.

METHODS

The required data were collected by searching the following key words according to MeSH: "colorectal cancer," "colorectal oncology," "colorectal carcinoma," "colorectal neoplasm," "colorectal tumors," "cost-effectiveness," "systematic review," and "meta-analysis." The following databases were searched: PubMed, Cochrane, Google Scholar, and Scopus. Two reviewers evaluated the articles according to the checklist of "assessment of multiple systematic reviews" (AMSTAR) tool.

RESULTS

Finally, eight systematic reviews were included in the study. The Drummond checklist was mostly used for assessing the quality of the articles. The main perspective was related to the payer and the least was relevant to the social. The majority of the cases referred to sensitivity analysis (in 76% of the cases) and the lowest point also was allocated to discounting (in 37% of cases). The Markov model was used most widely in the studies. Treatment methods examined in the studies were not cost-effective in comparison with the studied units. Among the screening methods, computerized tomographic colonography and fecal DNA were cost-effective. The average score of the articles' qualities was high (9.8 out of 11).

CONCLUSIONS

The community perspective should be taken into consideration at large in the studies. It is necessary to pay more attention to discounting subject in studies. More frequent application of the Markov model is recommended.

New insights into colorectal cancer screening and early detection tests

Colorectal cancer (CRC) is a common cancer in both men and women worldwide. Creating a diagnostic panel is necessary for early diagnosis which could lead to a better long-term survival in cancer patients. Colonoscopy every 10 years, starting at age 50, is the preferred CRC screening test. Many studies have been worked on potential diagnostic biomarkers of CRC. In this article, we described the recent evolutions in the development of CRC noninvasive screening assays. Recently, a multifunctional fecal DNA test has been available commercially in the USA. A few other US FDA-approved tests like Epi proColon® (Epigenomics AG, Berlin, Germany) are also available now. Although a new marker class for fecal occult blood test, a novel biomarker based on fecal bacteria in CRC patients and circulating tumor cells are under investigation, there is still a strong need to do more research for CRC screening strategies.

Clinical multi-omics strategies for the effective cancer management

Cancer is a global health issue as a multi-factorial complex disease, and early detection and novel therapeutic strategies are required for more effective cancer management. With the development of systemic analytical -omics strategies, the therapeutic approach and study of the molecular mechanisms of carcinogenesis and cancer progression have moved from hypothesis-driven targeted investigations to data-driven untargeted investigations focusing on the integrated diagnosis, treatment, and prevention of cancer in individual patients. Predictive, preventive, and personalized medicine (PPPM) is a promising new approach to reduce the burden of cancer and facilitate more accurate prognosis, diagnosis, as well as effective treatment. Here we review the fundamentals of, and new developments in, -omics technologies, together with the key role of a variety of practical -omics strategies in PPPM for cancer treatment and diagnosis.

BIOLOGICAL SIGNIFICANCE

In this review, a comprehensive and critical overview of the systematic strategy for predictive, preventive, and personalized medicine (PPPM) for cancer disease was described in a view of cancer prognostic prediction, diagnostics, and prevention as well as cancer therapy and drug responses. We have discussed multi-dimensional data obtained from various resources and integration of multisciplinary -omics strategies with computational method which could contribute the more effective PPPM for cancer. This review has provided the novel insights of the current applications of each and combined -omics technologies, which showed their powerful potential for the establishment of PPPM for cancer.