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.

Different Mechanism Involvement in the Formation of Colorectal Cancer; Mega Review

Colorectal cancer was infrequently diagnosed several decades ago. Nowadays, it is the world's fourth most deadly cancer with almost 900,000 deaths annually. Colorectal cancer had a low incidence several decades ago. However, it has become predominant cancer and now accounts for approximately 10% of cancer-related mortality in western countries. The ‘rise’ of colorectal cancer in developed countries can be attributed to the increasingly aging population, unfavorable modern dietary habits and an increase in risk factors such as smoking, low physical exercise and obesity. New treatments for primary and metastatic colorectal cancer have emerged, providing additional options for patients; these treatments include laparoscopic surgery for primary disease, more aggressive resection of metastatic disease (such as liver and pulmonary metastases), radiotherapy for rectal cancer and neoadjuvant and palliative chemotherapies. However, these new treatment options have had a limited impact on cure rates and long-term survival. Keywords: Colorectal cancer, Tumor marker, Hereditary colorectal cancer, Mediterranean diet.

Immunohistochemical expression of clusterin in colorectal carcinoma

Background and objective: Colorectal cancer is a heterogeneous malignancy characterized by a wide range of genetic and epigenetic alterations. Clusterin is a heterodimeric glycoprotein widely expressed in a variety of tissues and secreted in many body fluids. Increased clusterin expression has been reported in the normal colonic mucosa, benign polyps, and colorectal carcinoma. This study aimed to detect the frequency of the clusterin immunoexpression in colorectal carcinoma and determine its association with some clinicopathological parameters. Methods: Sixty formalin-fixed paraffin-embedded sections of colorectal adenocarcinoma were obtained and randomly selected from the histopathology laboratory at Rizgary Teaching Hospital and some private histopathology laboratories in Erbil city over two years between December 2016 and December 2018. All patients had been diagnosed to have primary colorectal adenocarcinoma and had undergone surgery. The clinicopathological characteristics of the tumors were revised, and the specimens were analyzed immunohistochemically using anticlusterin mouse monoclonal antibody. Results: Twenty eight cases (46.6%) were labeled as clusterin positive, while 32 cases (53.4%) were negative for clusterin expression. Clusterin expression was significantly associated with the tumor type (Non-mucinous) (P = 0.01) and tumor grade (well to moderately differentiated) (P = 0.03). At the same time, no significant association was found between clusterin immunoexpression and other clinicopathological characteristics like age, gender, tumor site, and tumor stage. Conclusion: Our study indicated that clusterin is overexpressed in some colorectal carcinomas and is significantly associated with histological type and grade. These results suggest that clusterin may play a role in colorectal carcinogenesis. Further studies are required to understand the possible mechanism of clusterin association with carcinogenesis and cancer progression. Keywords: Colorectal cancer; Clusterin; Immunohistochemistry.

Colorectal cancer disparities and African Americans: is it time to narrow the gap?

Colorectal cancer is the second most common cause of cancer death in both men and women. Although the overall incidence and mortality rates of colorectal cancer are declining, African Americans have significantly higher rates of colorectal cancer than Caucasians, and they have worse 5-year survival rates. This article reviews some of the contributing factors that lead to this racial disparity in colorectal cancer between these groups. The increase in poor health outcomes among African Americans is due to low socioeconomic standing, poor compliance, psychosocial barriers, and patient mistrust of healthcare providers and the healthcare system. Research on interventions to improve health outcomes is important to reduce the causes of these disparities. Keywords: colorectal cancer; screening; African Americans; Blacks; health disparities; interventions; public health

FACTORS AFFECTING DELAY IN DIAGNOSIS OF COLORECTAL CANCER: A CROSS-SECTIONAL STUDY; FROM TERTIARY CARE HOSPITAL OF KARACHI PAKISTAN

Background: CRC incidence is increasing in our region. There is no specific CRC control program or national cancer registry in Pakistan. Previously no data has been published on presentation and diagnosis delay of CRC in our region. This study is conducted to determine the factor affecting delay in presentation and diagnosis and to provide baseline information to launch a CRC control program. Primary objective is to determine factor causing delay in diagnosis of CRC. Secondary objective is to evaluate relationship between tumor site and stage of CRC with presenting symptoms and symptom duration. Methods: This project is a prospective cross-sectional study on 113 biopsy-proven CRC patients admitted to the surgical ward of civil hospital Karachi. Results: A total number of participants was 113. Presentation delay was observed in 83.2% of patients. The main reasons for a reported delay in the presentation were lack of patients’ knowledge that these symptoms may be cancer (60.4%), the wrong diagnosis by the primary physician (34.6%), or the patient didn’t want to visit the doctor (0.04%). Most tumors (95%) originated from the sigmoid and rectum. 38.9% and 44.2% of the patients diagnosed at Stage 4 and 3 respectively. Conclusions: This study revealed that CRC patients in Pakistan are facing delays in presentation and diagnosis. This is the reason behind diagnosis at the advanced stage with a poor prognosis. Based on this study findings CRC control program should be introduced to detect CRC at an early stage. Keywords: Colorectal cancer, Colon, Rectum, Cancer, Presentation delay, Diagnosis delay.

Evaluation Changes in Indicators of Oncological Service in Colorectal Cancer in East Kazakhstan Region

About 3.15 million new cases of colorectal cancer (CRC) are predicted and it is expected that about 1.62 million human will die from this pathology, according to the forecasts of the International Agency for Research on Cancer in 2040. To this aim, an analysis studying studying the indicators of the oncological service for CRC also makes it possible to evaluate the ongoing anti-cancer measures in East Kazakhstan region. Aim. Evaluate some indicators of the oncological service at CRC in East Kazakhstan region in 2009 to 2018. Materials and methods. The research material was data from the Ministry of Health of the Republic of Kazakhstan – annual form No. 7 and 35 regarding CRC (ICD 10 – C18-21) for 2009-2018 in East Kazakhstan region – incidence, mortality, early diagnosis, neglect, morphological verification. A retrospective study using descriptive and analytical methods of biomedical statistics was used as the main method. Results and discussion. For 2009-2018, 3,661 new cases of CRC were registered in East Kazakhstan region for the first time. The incidence of CRC was 25.30/0000 and in dynamics tended to increase from 21.90/0000 (2009) to 25.70/0000 in 2018, the difference was statistically significant (t=1.99 and p=0.047). The mortality rate from CRC tended to decrease from 15.50/0000 to 14.70/0000 (p=0.591), and the average annual mortality rate from CRC was 15.60/0000. The indicators of early diagnosis (the proportion of patients with stage I-II) improved from 58.8% (2009) to 62.3% in 2018, and, accordingly, the indicators of the proportion of neglected patients significantly decreased with stage III (from 25.5% to 20.8%), while with stage IV (from 15.7% to 16.9%) there is a slight increase. The indicators of morphological verification in CRC improved from 90.5% to 98.6% during the studied years. Conclusion. An improvement in the indicators of morphological verification and early diagnosis of CRC was found. The obtained results are recommended to be used for monitoring anti-cancer measures in the region. Keywords: colorectal cancer, incidence, mortality, early diagnosis, neglect, morphological verification.

Mapping the Colorectal Cancer Screening Scientific Landscape in South Africa: A Bibliometric Analysis to Identify Inequalities

Background This paper maps scientific publications to identify areas of CRC screening that are currently receiving greatest emphasis in South African research, as means, to identify the inequality in CRC screening research. Reviewing the publications can assist to identify research funding and research capacity gaps. It can also identify potential for collaboration of authors and institutions to reduce the inequalities. Methods We used bibliometrics to identify and map the scientific publications on CRC screening related to South Africa (SA).The search utilised three databases, namely: Web of Science, Scopus and PubMed to identify articles published between January 2000 to August 2020. We identified the document by type, research areas, journal type, affiliated countries and research organisations, authors with most publications, and funding sources. Results Forty-eight of the 368 publications were included for bibliometric analysis. Of these, there were 88% original articles; 6% were reviews; 4% were books and 2% were abstracts of meetings. The top CRC screening research areas were oncology (21%); gastroenterology and hepatology (13%), public, environmental, occupational health (13%) and genetics and heredity (13%).The top four journals that have published the CRC screening related to South Africa were the South African Medical J. Surgery (10%); South African Medical Journal (7%); Clinical Genetics (5%) and Colorectal Diseases (5%). 19% of articles were published in 2019. There were 28 (58%) articles with first authors from South Africa. There were ten publications without funding declared (21%). The top five research organisations from South Africa that published the most CRC screening research were University of Witwatersrand (36%); University of Western Cape (18%); University of Pretoria (14%); University of Cape Town and KwaZulu-Natal (11%). Conclusion Research and development of novel CRC screening technologies cannot be overemphasised, as catalyst for diverse screening alternatives that are less invasive, affordable and accessible to all those in need to expand access, coverage and increase uptake at local level. Keywords: Colorectal cancer; Bibliometric; Screening; Colonoscopy; Scientific landscape; Inequalities; Cancer; South Africa.

Diagnosis of molecular subtypes of colorectal cancer using immunohistochemistry

Colorectal cancer ranks third in the morbidity structure among all malignant tumors and includes sporadic and hereditary neoplasms. Cancer genome sequencing has revealed numerous mutation variants that determine the ways colorectal carcinoma progresses. The course, prognosis, and management strategy of the disease vary greatly depending on the subtype of a molecular tumor. This literature review discusses the latest data on the variants of colorectal cancer oncogenesis and presents the phenotypic model classification based on them. Immunohistochemistry (IHC) is suggested for determining the individual tumor characteristics. The article also clarifies the Bethesda panel used to detect microsatellite instability, markers for Lynch syndrome, and a list of IHC markers for determining the phenotypic model of colorectal carcinoma. Keywords: colorectal cancer, phenotypic models, consensus molecular subtypes (CMS), immunohisto-chemistry, Bethesda panel, Lynch syndrome

PU.1 is a nuclear factor of immunocompetent cells of tumor stroma in colorectal cancer

Introduction. Tumor-associated macrophages (TAMs) are traditionally considered to be a pro-tumor fac-tor that promotes the growth of various tumors; however, for colorectal carcinomas (CRC), the prognostic significance of TAMs has not been fully determined, which may be due to the lack of macrophage markers suitable for this tumor type. The aim of this work was to study the expression of the nuclear marker of stromal cells PU.1 in colorectal tumors and its association with the clinical and morphological tumor characteristics. Materials and methods. We performed an immunohistochemical analysis to assess the expression of PU.1, CD68, and CD20 in 85 primary CRCs. The Mann-Whitney test was used to determine statistically significant differences in independent groups. Correlation analysis of the expression of the studied protein was carried out by determining the Spearman’s rank correlation coefficient. Differences were considered statistically significant at p <0.05. Results. We analyzed the expression of PU.1, CD68, and CD20 in CRC and detected positive PU.1 and CD68 expressions in tumor stromal cells in all of the studied samples. Expression of CD20 was observed in 87% of cases. We showed that in colorectal tumors all CD68+ or CD20+ cells express PU.1 and that PU.1 and CD20 were significantly associated with the disease stage (p=0.036 and p=0.002) and the presence or absence of regional metastases (p=0.022 and p=0.007). In addition, PU.1 showed a significant correlation with the distant metastases’ presence and tumor localization (p=0.031 and p=0.022). Higher content of PU.1 was typical for colon tumors without metastases. CD20 also showed a significant association with tumor size (p=0.025). No significant correlations with clinical and morphological features were found for CD68. We also demonstrated that the number of PU.1+ cells in tumors significantly positively correlates with CD68 (r=0.231, p=0.036) and CD20 (r=0.267, p=0.015). Conclusion. The results of this study indicate that PU.1 can be considered as an independent marker of a favorable prognosis in CRC patients. Keywords: colorectal cancer, expression, CD20, CD68, PU.1, macrophages, B-cells

EXPRESSION OF VASCULOENDOTHELIAL AND PLATE GROWTH FACTORS IN PRIMARY COLORECTAL TUMOR AS A PREDICTOR OF EARLY RECURRENCE

The prognostic factors that determine colorectal cancer (CRC) treatment are disease status, tumor grade, microsatellite instability, invasion degree, and the index of proliferative activity. However, the assessment of the adjuvant chemotherapy in colorectal cancer does not imply the assessment of angiogenic factors in a primary tumor. The aim of the paper is to evaluate the prognostic role of PDGFAA and VEGFA expression in tumor tissue of stages II/III colorectal cancers. Materials and Methods. Paraffin blocks of primary CRC tumor (n=50) were used as study material. Immunohistochemistry (IHC) was used to examine the expression of vasculoendothelial and platelet growth factors and calculate IHC score in the tumor parenchyma and CRC stroma. Results. According to IHC staining, CRC tumor expresses VEGFA and PDGFAA factors in 92 % of cases, in the resection line – in 37 % of the samples. There were no differences in VEGFA and PDGFAA expression in tumor parenchyma in CRC, depending on the process stage and grade degree. The cumulative risk of disease progression within a year after surgery in patients with stage II/III CRC with VEGFA+PDGFAA overexpression in the primary tumor is 4.9 times higher (CI 2.123–11.089, p=0.011) compared to the group of patients with reduced expression of the studied angiogenic factors. Conclusions. The data obtained suggest that co-expression of angiogenic VEGFA and PDGFAA factors in the tumor may reflect the initial CRC regarding neoangiogenesis. If VEGFA and/or PDGFAA IHC score is more or equal to 6, the risk of disease recurrence within 1 year from the start of medical observation increases, which is an unfavorable prognostic factor. Keywords: colorectal cancer, vasculoendothelial growth factor, platelet growth factor, adjuvant chemotherapy. Прогностическими факторами, определяющими тактику лечения при колоректальном раке (КРР), являются стадия заболевания, степень дифференцировки опухоли, микросателлитная нестабильность, степень инвазии, индекс пролиферативной активности. При этом оценка эффективности адъюватной химиотерапии при КРР не предполагает оценку ангиогенных факторов в первичной опухоли. Цель работы – оценить прогностическую роль экспрессии PDGFAA и VEGFA в опухолевой ткани на II–III стадиях колоректального рака. Материалы и методы. В качестве материала для исследования использованы парафиновые блоки первичной опухоли КРР (n=50). С помощью метода ИГХ исследована экспрессия васкулоэндотелиального и тромбоцитарного факторов роста путем расчета ИГХ-балла в опухолевой паренхиме и строме КРР. Результаты. По результатам ИГХ-окрашивания опухоль КРР экспрессирует факторы VEGFA и PDGFAA в 92 % случаев, в линии резекции – в 37 % образцов. Отличий в экспрессии VEGFA и PDGFAA в опухолевой паренхиме при КРР в зависимости от стадии процесса, степени дифференцировки выявлено не было. Кумулятивный риск прогрессирования заболевания в течение года после операции у больных с КРР II–III стадий при гиперэкспрессии VEGFA+PDGFAA в первичной опухоли выше в 4,9 раза (ДИ 2,123–11,089, р=0,011) по сравнению с группой пациентов со сниженной продукцией изученных ангиогенных факторов. Выводы. Полученные данные позволяют предполагать, что коэкспрессия ангиогенных факторов VEGFA и PDGFAA в опухоли может отражать исходный профиль КРР в отношении неоангиогенеза. При ИГХ-балле VEGFA и/или PDGFAA выше или равном 6 возрастает риск рецидива заболевания в течение 1 года от момента начала наблюдения, что является неблагоприятным прогностическим фактором. Ключевые слова: колоректальный рак, васкулоэндотелиальный фактор роста, тромбоцитарный фактор роста, адъювантная химиотерапия.