Introduction: Colorectal cancer (CRC) survivors may experience functional deficits due to cancer-associated impairments. However, we do not understand their type and extent of functional deficits and how we could measure the associated cause of functional deficits, such as fatigue. As the survival of CRC survivors improves, the burden of living with functional deficits can be high. Purpose: My research program aims to understand (1) the functional changes and deficits that CRC survivors experience and (2) how to best measure fatigue in this population. Methods: To address the first aim, we used the data from the International Study of the Risk Factors for Gastrointestinal Bleeding and Cardiovascular Events after Gastrointestinal Bleeding to examine individuals’ functional abilities within 1 year of gastrointestinal cancer diagnosis (CRC being the most prevalent type). For the second aim, we conducted a systematic review on fatigue measures in adults with inflammatory bowel disease (IBD) because the causes, severity, and impact of IBD and CRC- related fatigue might be similar. We identified fatigue measures in the IBD population, appraised their psychometric properties, and recommended the most psychometrically robust and feasible measures for clinical and research use, indicating the optimal measures for CRC survivors. Results: After gastrointestinal cancer diagnosis, the majority (~70%) performed fewer functional tasks, mostly in the instrumental activities of daily living; and about 44% had more difficulty walking. Our review identified 16 measures, reviewed the content and psychometric properties, and recommended the Functional Assessment of Cancer Therapy Instrument-Fatigue and the IBD- Fatigue scale for research and clinical use in IBD and CRC populations. Conclusion: We provided a novel understanding of the functional deficits that CRC survivors experience and recommended the optimal measures for assessing CRC-related fatigue. As CRC survivors commonly experience fatigue, fatigue should be measured to understand its role in the functional abilities of CRC survivors. / Thesis / Master of Science Rehabilitation Science (MSc) / More people are living with colorectal cancer (CRC), but may have problems performing their daily activities (i.e. functional problems) due to cancer-associated impairments. However, we do not understand the extent of these impairments and functional problems. We used a sample of people with newly-diagnosed gastrointestinal cancer (CRC being the most common type) to understand their type and extent of functional problems. People were found to participate less in functional activities and particularly have more difficulty walking after a cancer diagnosis. Fatigue is common among those with CRC and may primarily cause functional problems. However, it is not commonly measured, and it is unclear how to best measure fatigue among them. Therefore, we reviewed key qualities of 16 fatigue measures in a similar population (inflammatory bowel disease, IBD) and recommended the Functional Assessment of Cancer Therapy Instrument-Fatigue and the IBD-Fatigue scale (English) as the most promising measures for those with CRC.

Background: Analytical frameworks (AF) are graphical representation of the key questions answered by a systematic review and can support the development of guideline recommendations. Our objectives are to a) conduct a systematic review to identify, describe and compare all AFs published as part of a systematic and guideline development process related to colorectal cancer (CRC); and b) to use this case study to develop guidance on how to conduct systematic reviews of AFs. Methods: We conducted a systematic review and searched Medline and Embase from 1996 until December 2020. We also manually searched guideline databases and websites. We identified all guidelines in CRC that utilized an AFs and all systematic reviews in primary prevention, screening, and diagnosis of CRC that used AFs. We assessed quality of the guidelines using the Appraisal of Guidelines for Research and Evaluation II tool. The systematic review was registered in PROSPERO, registration CRD42020172117. Results: We screened 34,505 records and identified 1166 guidelines on CRC and 3127 systematic reviews, of which 5 met our inclusion criteria identifying a total of 4 AFs in colorectal cancer. We describe our search strategy and methods for conducting systematic reviews for AFs. Conclusion: Few guidelines and systematic reviews are utilizing AFs in the development of recommendations. We developed methods for conducting a systematic review on AF / Thesis / Master of Science (MSc) / Analytical frameworks are graphical diagrams that represent key questions with flow of resining from population to outcome. We conducted a systematic review to identify all analytical frameworks in colorectal cancer and in the process we developed guidance on how to conduct a systematic review for analytical frameworks. We identified four analytical frameworks, one in primary prevention, and three in screening of colorectal cancer. We found only a few clinical practice guidelines that utilized analytical frameworks in the development of the recommendations. We developed methods for conducting a systematic review of analytical frameworks.

Colorectal cancer (CRC) is one of the most prevalent cancers worldwide and is recognized as the second leading cause of cancer-related deaths in North America. CRC follows a hierarchal tumor organization, the root being a small population of self-renewing and highly tumorigenic colon cancer stem cells (CSC). There is an epigenetic signature that exists within these colon CSCs contributing to their maintenance and dynamic plasticity. A key hallmark of this colon CSC epigenetic signature is the Histone-3 Lysine-9 di-methylation (H3K9me2) histone mark which is overrepresented in many types of cancer. Pharmacological modulation of this epigenetic signature (i.e through H3K9me2 modulation) serves as a novel way to selectively target and eliminate human CSCs while sparing normal progenitor cells. Direct inhibitors of key methyltransferases such as G9a, have been identified to have high specificity, however none of these inhibitors have shown success during early stages of clinical trials, leaving us to question the clinical relevance. My research has shown that the overexpression of histone methyltransferase G9a in colon cancer serves as a risk factor for patients and is associated with shorter-relapse free survival. G9a activity has been shown to be essential for the maintenance of embryonic-like transcriptional signature which promotes self-renewal, tumorigenicity and an undifferentiated state. This work provides insights into the role of G9a as a driver of a cancer stem cell phenotype. To combat the toxicity and issues associated with targeting the catalytic activity of G9a, I utilized a phenotypic screening pipeline consisting of thousands of clinically-approved compounds, and identified CSC-bioactive epigenetic inhibitors showing promise in CSC-like models. RNA-seq profiling, dose response treatments and molecular techniques were used to confirm the selectivity of these candidates to colon-CSC like cells with minimal impact on normal progenitors. The lead candidate compound, vanoxerine (VXN) restricts organoid-initiating capacity of patient derived colon CSCs in serial 3D organoid formation assays that I developed throughout my research project. Using two murine syngeneic models resembling microsatellite instability and stability in CRC, I found this compound to be successful in decreasing primary tumor volumes compared to vehicle control mice, through epigenetic reprogramming and infiltration of immune cells. Drug treated tumors that were harvested, dissociated and re-injected into secondary mice showed diminished tumor initiating capacity compared to vehicle controls. Furthermore, the target of vanoxerine, SLC6A3, was investigated and the expression pattern characterized revealed a new potential biomarker for colon cancer stem cells. This SLC6A3-G9a axis discovered for the first time in colon cancer and serves as a novel and important pathway to block H3K9me2 deposition in CRC, rewiring the CSC epigenome and suppressing neoplastic self-renewal and tumor-initiating functions. Together, the identified repurposed compound selectively targets and modulates the epigenetic signature of CSCs which diminishes the tumor initiating function of these cells. This hints at an interesting interaction between CRC stemness and tumor immunology, a promising future therapeutic avenue.

The Notch signalling pathway is an evolutionary conserved pathway, named after the Notch receptors, Notch1-4 in mammals, which upon cell-cell contact and ligand binding releases the intracellular domain (NICD). NICD translocates into the nucleus where it binds the transcriptional repressor RBP-Jk, which together with co-activators belonging to the Mastermind-like family of proteins form a transcriptional activation complex. This complex activates genes controlling cell fate decision, embryonic development, proliferation, differentiation, adult homeostasis and stem cell maintenance. On the other hand, disrupted Notch signalling may result in pathological conditions like cancer, although the mechanisms behind the disruption are often complex and in many cases largely unknown. Notch1 drives the lymphocyte differentiation towards a T-cell fate and activating mutations in the gene have been suggested to be involved in T-cell lymphoma. In paper I, genetic alterations in Notch1 and the Notch1 regulating gene CDC4 were investigated in tumours from murine T-cell lymphoma induced with phenolphthalein, 1,3-butadiene or 2’,3’-dideoxycytidine. We identified activating Notch1 mutations in 39% of the lymphomas, suggesting that Notch1 is an important target gene for mutations in chemically induced lymphomas. While it is known that constitutively activated Notch signalling has a clear oncogenic function in several solid malignancies as well, the molecular mechanisms are less known in this context. Unpublished data of our lab, together with other recent studies, suggest that mutations of Notch and Notch-related genes per se are uncommon in solid malignancies including colorectal cancer, while a growing body of evidence indicates that aberrant Wnt/b-catenin signalling may result in pro-tumoural Notch activation in these contexts. In paper II, we therefore investigated potential transcriptional interactions between the Notch and Wnt signalling pathways in colorectal cancer cell lines. The proximal Notch and Wnt pathway gene promoters were bioinformatically identified and screened for putative TCF/LEF1 and RBP-Jk sites. In canonical Wnt signalling, Apc negatively regulates b-catenin leading to repression of TCF/LEF1 target genes. Upon repression of the Wnt pathway we observed that several genes in the Notch pathway, including Notch2, were transcriptionally downregulated. We also confirmed binding of Lef1 to Notch2 as well as other Notch pathway gene promoters and luciferase assays showed an increased activity for at least one LEF1/TCF-site in the Notch2 promoter upon co-transfection of HT29 or HCT116 cells with mutated b-catenin. HT29 cell lines were also treated with the g-secretase inhibitor DAPT, leading to inactivation of the Notch pathway by preventing release of NICD. However, results showed no effects on Apc, b-catenin or their target cyclin D1. Taken together, these results indicate that the Wnt pathway may function as a regulator of the Notch pathway through the TCF/LEF1 target gene program in colon cancer cell lines. In summary, Notch pathway deregulation is of importance in both murine T-cell lymphoma and human colorectal cancer, although the mechanisms differ. The current results give new insights in Notch pathway alterations as well as the signalling networks in which the Notch pathway interacts, and thus increase the understanding of Notch’s involvement in malignant diseases. / Studies on molecular genetic alterations in colorectal cancer

Colorectal carcinoma is an important, feasible and attractive target for chemoprevention because a) it is a major cause of mortality in the United States and in other developed countries worldwide, b) there is a high mortality associated with advanced disease, c) there is a well described molecular carcinogenesis pathway and d) recent advances in molecular genetics will improve the ability to identify high-risk subjects. Epidemiological data, colonoscopic screening and advances in molecular genetics has made possible the identification and selection of subjects at increased risk of developing colorectal cancer. Due to this new information it may be possible to impede malignant cellular transformation with drugs. Such intervention with relatively simple maneuvers, such as a low daily dose of aspirin, can potentially reduce mortality from colorectal cancer. Prospective trials need to confirm experimental and epidemiological data supporting the efficacy of aspirin and other NSAID as chemopreventive agents before they can be used in the general population at risk. To use cancer chemopreventives effectively and safely in an asymptomatic population, the risks should be minimized and the benefits maximized by determination of optimal dose, schedule and chemopreventive mechanism of the NSAID. By linking the putative mechanism of drug action to effect endpoints, we expect to know whether the chemopreventive intervention is likely to be effective in a given individual.

BACKGROUND: Colonoscopy performance by gastroenterologists has been shown to be associated with lower rates of developing interval colorectal cancer. However, it is unclear if this difference among specialists stems from a difference in meeting colonoscopy quality indicators. OBJECTIVE: The purpose of this study is to determine and compare the rates of colonoscopy quality indicators between different specialties. DESIGN: This is a cohort study of patients undergoing screening colonoscopy investigating quality metrics as compared by the proceduralist specialty. SETTING: All screening colonoscopies performed at the Cleveland Clinic between 2012 and 2014 were followed by manual chart review. PATIENTS: Average-risk patients, ≥50 years of age, who had a complete screening colonoscopy were included. MAIN OUTCOME MEASURES: Adenoma detection rate, cecal intubation rate, withdrawal time, and other nonestablished overall and segment-specific rates were calculated and compared using t tests. RESULTS: A total of 4151 patients were included in the analysis. Colonoscopies were performed by 54 (64.3%) gastroenterologists, 21 (25%) colorectal surgeons, and 9 (10.7%) general surgeons. Gastroenterologists had the highest overall adenoma detection rate (28.6 ± 1.2; p < 0.001), followed by colorectal surgeons (24.3 ± 1.5) and general surgeons (18.4 ± 2.3), as well as the highest adenoma detection rate in men (34.7 ± 1.3; p < 0.001), followed by colorectal surgeons (28.2 ± 1.6) and general surgeons (23.7 ± 2.6). Similarly, gastroenterologists had the highest adenoma detection rate in women (24.3 ± 1.1; p < 0.001), followed by colorectal surgeons (21.6 ± 1.4) and general surgeons (12.9 ± 2.0). Withdrawal time was the longest among general surgeons (11.1 ± 5.5; p = 0.041), followed by colorectal surgeons (10.94 ± 5.2) and gastroenterologists (10.16 ± 1.26). LIMITATIONS: We could not adjust for some procedure-related details such as retroflexion in the right colon and the use of end-of-scope devices. CONCLUSIONS: In this study, only gastroenterologists met the currently accepted overall and sex-specific adenoma detection rate benchmarks. They also outperformed nongastroenterologists in many other nonestablished quality metrics. See Video Abstract at http://links.lww.com/DCR/B232.

Indiana University-Purdue University Indianapolis (IUPUI) / Colorectal cancer (CRC), the third leading cause of cancer-related death in the U.S., could largely be prevented if more people had polyps removed via colonoscopies. Embarrassment has been identified as one important barrier to colonoscopy, but little is known about embarrassment in this context. Further, there is no instrument available to measure this construct. Therefore, the purpose of this study was to develop a reliable and valid instrument to measure colonoscopy-related embarrassment. The study aims were to: 1) estimate reliability and validity of a new instrument, the Colonoscopy Embarrassment Scale (CES); 2) examine relationships among demographic/personal characteristics, health beliefs, and CES scores; 3) examine relationships among demographic/personal characteristics, physician recommendation, health beliefs, and colonoscopy compliance; and 4) evaluate participants’ perceptions of aspects of having a colonoscopy that are most embarrassing and their suggestions for reducing embarrassment. The Health Belief Model and Transtheoretical Model of Change provided theoretical support for this study. Participants were HMO members aged 50-65 years (n=234). Using a cross-sectional, descriptive research design, data were collected using a mailed survey. The response rate was 56%. Data were analyzed using independent samples t-tests, correlations, Chi Square, and regression. Results showed that the six-item CES had internal consistency (Cronbach’s alpha of .89) and construct validity. Lower income, higher BMI, lower CRC knowledge, higher barriers, and lower self-efficacy were related to higher CES scores (or more embarrassment). Higher CRC knowledge, lower barriers, higher self-efficacy, and a physician recommendation for the test were related to higher compliance with colonoscopy. Lower barriers, higher self-efficacy, and a physician recommendation were predictive of compliance with colonoscopy. In conclusion, embarrassment is a significant barrier to colonoscopy, yet there are steps that can be taken to reduce embarrassment such as increasing privacy and limiting bodily exposure. The CES is a tool that can be used to measure colonoscopy-related embarrassment and the results could be used in developing further interventions to reduce embarrassment, leading to increased colonoscopies and lower mortality.

Introduction: Colorectal cancer (CRC) is one of the most frequent malignancies and affects approximately 5% of worldwide population. More than 75% of CRC cases represent sporadic forms. Susceptibility to nonhereditary CRC is significantly influenced by polymorphisms and mutations in low-penetrance genes. Variations in biotransformation and DNA repair genes may result in acumulation of toxins and DNA damage in cells leading to the development of cancer. Furthermore, different gene expression profiles of membrane transporters affecting the accumulation of anticancer drugs in tumour cells, e.g. ABC drug transporters, may largely influence inter-individual variability in drug response and chemotherapy outcome. The aim of this study was to evaluate the role of genetic and lifestyle factors in the risk of onset and progression of colorectal cancer. This study followed selected genetic alterations in xenobiotic-metabolizing enzymes (CYP1B1, GSTM1, GSTT1, GSTP1, NQO1 and EPHX1) and genes involved in response to DNA damage (CHEK2 and NBN), as potential CRC susceptibility factors. Another aim of this study was to investigate expression profile of all human ABC transporter genes to follow their prognostic and predictive potential in colorectal carcinoma. Materials and methods: The polymorphisms and other...

Colorectal cancer is one of the most common type of malignity. Despite of the existence of numerous studies focused on this carcinoma, there are still many unknown features regarding its diagnosis, treatment or prognosis. In the thesis we focused on the identification of novel prognostics markers that could be useful for the stratification of patients based on the disease outcomes. In the first study we immunohistochemically assessed expression of two proteins associated with cancer stem cells in the samples of primary colorectal cancer and matched liver metastasis. Goal of the study was to evaluate relation among expression of CD44 and CD133 and overall survival and disease free interval in our set of patients. We observed that increased ratio of CD133 positive compared to CD133 negative tumor glands resulted in longer disease free interval, finding which is opposite to the general view on the CD133 role in the cancer development. Our hypothesis is that we analyzed confined group of patients and followed a bit different goal, where we measured ratio between positive and negative glands in the view-field and not the intensity of staining as the previous studies did. Our second study was focused on the transcriptional analysis of the selected set of twelve genes using frozen samples from colorectal...

Introduction Aspirin has been associated with a reduction in mortality in patients diagnosed with colorectal cancer (CRC). A possible mechanism for this is related to the programmed cell death 1 (PD-1) immune checkpoint pathway. Aspirin may have a synergistic effect with PD-1 inhibitors via inhibition of prostaglandin E2 (PGE2) production, which can reverse the ability of tumor cells to evade the immune system. This appears to be strongest in cancers that express PI3 kinase (PI3K) signaling activity, which aspirin downregulates. However, the benefit of pre-diagnosis aspirin use on CRC overall survival (OS) and cancer-specific survival is still controversial, and most studies have been performed in racially homogenous populations. Our study examines the effect of pre-diagnosis aspirin therapy on OS in a racially diverse group of patients with CRC. Methods This is a retrospective chart review of 782 patients diagnosed with CRC from January 2007 to December 2020. Kaplan-Meier curve was created to study the association of aspirin exposure compared to no exposure on OS. In addition, univariate and multivariate binary logistic regression analyses were done to investigate potential predictors of survival. Results Of the 782 patients with CRC, 55.1% were males, 22.2% whites, 58.5% Asians, and 17.7% Pacific-Islanders. Moreover, 38.4% of the patients had a history of aspirin use, 79% of them used it for more than one year. There were more patients with hypertension (HTN), hyperlipidemia (HLD), diabetes mellitus (DM), and chronic kidney disease (CKD) among those with a history of aspirin use. There was no difference in one, three, and five-year OS among aspirin users compared to non-users, p-value = 0.63. Age, grade, and stage were potential predictors of worsened OS. However, treatment with chemotherapy and CKD were potential predictors of worsened OS on univariate analysis only. No significant association was noticed with gender, tumor location, or other associated comorbidities. Conclusion The effect of pre-diagnosis aspirin use on CRC survival is not clear. In this retrospective analysis of a racially diverse population of CRC patients, we found that aspirin use was not associated with improved OS. Therefore, physicians should be careful about using aspirin as adjuvant therapy in CRC patients until high-quality prospective data are available, given the potential associated complications.