The natural history of colorectal adenomas and early cancer

Colorectal polyps increase the glycolytic activity

In colorectal cancer (CRC) energy metabolism research, the precancerous stage of polyp has remained rather unexplored. By now, it has been shown that CRC has not fully obtained the glycolytic phenotype proposed by O. Warburg and rather depends on mitochondrial respiration. However, the pattern of metabolic adaptations during tumorigenesis is still unknown. Understanding the interplay between genetic and metabolic changes that initiate tumor development could provide biomarkers for diagnosing cancer early and targets for new cancer therapeutics. We used human CRC and polyp tissue material and performed high-resolution respirometry and qRT-PCR to detect changes on molecular and functional level with the goal of generally describing metabolic reprogramming during CRC development. Colon polyps were found to have a more glycolytic bioenergetic phenotype than tumors and normal tissues. This was supported by a greater GLUT1, HK, LDHA, and MCT expression. Despite the increased glycolytic activity, cells in polyps were still able to maintain a highly functional OXPHOS system. The mechanisms of OXPHOS regulation and the preferred substrates are currently unclear and would require further investigation. During polyp formation, intracellular energy transfer pathways become rearranged mainly by increasing the expression of mitochondrial adenylate kinase (AK) and creatine kinase (CK) isoforms. Decreased glycolysis and maintenance of OXPHOS activity, together with the downregulation of the CK system and the most common AK isoforms (AK1 and AK2), seem to play a relevant role in CRC development.

Multivariable models for advanced colorectal neoplasms in screen-eligible individuals at low-to-moderate risk of colorectal cancer: towards improving colonoscopy prioritization

Background

Advanced colorectal neoplasms (ACNs), including colorectal cancers (CRC) and high-risk adenomas (HRA), are detected in less than 20% of persons aged 50 years or older who undergo colonoscopy. We sought to derive personalized predictive models of risk of harbouring ACNs to improve colonoscopy wait times for high-risk patients and allocation of colonoscopy resources.

Methods

We characterized colonoscopy indications, neoplasia risk factors and colonoscopy findings through chart review for consecutive individuals aged 50 years or older who underwent outpatient colonoscopy at The Ottawa Hospital (Ottawa, Canada) between April 1, 2008 and March 31, 2012 for non-life threatening indications. We linked patients to population-level health administrative datasets to ascertain additional historical predictor variables and derive multivariable logistic regression models for risk of harboring ACNs at colonoscopy. We assessed model discriminatory capacity and calibration and the ability of the models to improve colonoscopy specificity while maintaining excellent sensitivity for ACN capture.

Results

We modelled 17 candidate predictors in 11,724 individuals who met eligibility criteria. The final CRC model comprised 8 variables and had a c-statistic value of 0.957 and a goodness-of-fit p-value of 0.527. Application of the models to our cohort permitted 100% sensitivity for identifying persons with CRC and > 90% sensitivity for identifying persons with HRA, while improving colonoscopy specificity for ACNs by 23.8%.

Conclusions

Our multivariable models show excellent discriminatory capacity for persons with ACNs and could significantly increase colonoscopy specificity without overly sacrificing sensitivity. If validated, these models could allow more efficient allocation of colonoscopy resources, potentially reducing wait times for those at higher risk while deferring unnecessary colonoscopies in low-risk individuals.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-021-01965-5.

Endoscopy infection control strategy during the COVID-19 pandemic: experience from a tertiary cancer center in Brazil

OBJECTIVES

Strategic planning for coronavirus disease (COVID-19) care has dominated the agenda of medical services, which have been further restricted by the need for minimizing viral transmission. Risk is particularly relevant in relation to endoscopy procedures. This study aimed to describe a contingency plan for a tertiary academic cancer center, define a strategy to prioritize and postpone examinations, and evaluate the infection rate among healthcare workers (HCWs) in the endoscopy unit of the Cancer Institute of the State of São Paulo (ICESP).

METHODS

We created a strategy to balance the risk of acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and to mitigate the effects of postponing endoscopic procedures in oncological patients. A retrospective analysis of prospectively collected data on all endoscopies between March and June 2020 compared with those during the same period in 2019 was carried out. All HCWs were interviewed to obtain clinical data and SARS-CoV-2 test results.

RESULTS

During the COVID-19 outbreak, there was a reduction of 55% in endoscopy cases in total. Colonoscopy was the most affected modality. The total infection rate among all HCWs was 38%. None of the senior digestive endoscopists had COVID-19. However, all bronchoscopists had been infected. One of three fellows had a serological diagnosis of COVID-19. Two-thirds of all nurses were infected, whereas half of all technicians were infected.

CONCLUSIONS

In this pandemic scenario, all endoscopy services must prioritize the procedures that will be performed. It was possible to maintain some endoscopic procedures, including those meant to provide nutritional access, tissue diagnosis, and endoscopic resection. Personal protective equipment (PPE) seems effective in preventing transmission of COVID-19 from patients to digestive endoscopists. These measures can be useful in planning, even for pandemics in the future.

Colorectal Cancer Screening Uptake: Differences Between Rural and Urban Privately-Insured Population

Earlier studies investigated rural-urban colorectal cancer (CRC) screening disparities among older adults or used surveys. The objective was to compare screening uptake between rural and urban individuals 50–64 years of age using private health insurance. Data were analyzed from 58,774 Blue Cross Blue Shield of Nebraska beneficiaries. Logistic regression was used to assess the association between rural-urban and CRC screening use. Results indicate that rural individuals were 56% more likely to use the Fecal Occult Blood Test (FOBT) compared with urban residents, but rural females were 68% less likely to use FOBT. Individuals with few Primary Care Physician (PCP) visits and rural-women are the least to receive screening. To enhance CRC screening, a policy should be devised for the training and placement of female PCP in rural areas. In particular, multilevel interventions, including education, more resources, and policies to increase uptake of colorectal cancer screening, are needed. Further research is warranted to investigate barriers to CRC screening in rural areas.

Natural and synthetic retinoids in preclinical colorectal cancer models

Colorectal cancer (CRC) remains a leading cause of cancer-related morbidity and mortality worldwide. Although targeted therapy in combination with chemotherapy in CRC prolongs the overall survival of patients with metastatic disease, acquired resistance and relapse hinder their clinical benefits. Moreover, patients with some specific genetic profile are unlikely to benefit from targeted therapy, suggesting the need for safe and effective treatment strategies. Retinoids, comprising of natural and synthetic analogs, are a class of chemical compounds that regulate cellular proliferation, differentiation, and cell death. Retinoids have been used in the clinic for several leukemias and solid tumors, either as single agents or in combination therapy. Furthermore, retinoids have shown potent chemotherapeutic and chemopreventive properties in different cancer models, including CRC. In this review, we summarize the major preclinical findings in CRC in which natural and synthetic retinoids showed promising antitumor activities and stress on the proposed mechanisms of action. Understanding of the retinoids' antitumor mechanisms would provide insights to support and warrant their development in the management of CRC.

Overexpression of SAPCD2 correlates with proliferation and invasion of colorectal carcinoma cells

Background

Suppressor anaphase-promoting complex domain containing 2 (SAPCD2) is a novel gene playing important roles in the initiation, invasion, and metastasis of several malignancies. However, its role in colorectal carcinoma (CRC) still remains unclear.

Method

In this study, we investigated the expression and biological function of SAPCD2 in CRC. Immunohistochemistry (IHC) for SAPCD2 was performed in 410 pairs of CRC specimens and corresponding normal epithelial tissues, and in 50 adenoma tissues. Clinical pathological factors were analyzed in relation to the expression of SAPCD2. The biological functions of SAPCD2 in CRC cells and its effect on cell cycle were investigated in vitro and in vivo through gain/loss-of-function approaches.

Results

IHC showed that SAPCD2 expression was significantly higher in CRC tissues compared to adenoma and normal epithelium tissues and was correlated with tumor location (p = 0.018). SAPCD2 significantly promoted cell proliferation, migration, and invasion both in vitro and in vivo (p < 0.05). In addition, SAPCD2 knockdown in CRC cells was associated with reduced G₁/S transition, while overexpression caused G₂/M phase arrest (p < 0.05).

Conclusions

In sum, SAPCD2 is overexpressed in CRC tissues and plays a critical role in CRC progression. Therefore, it might represent a promising therapeutic target for CRC treatment.

Mutation Profiling of Premalignant Colorectal Neoplasia

Accumulation of allelic variants in genes that regulate cellular proliferation, differentiation, and apoptosis may result in expansion of the aberrant intestinal epithelium, generating adenomas. Herein, we compared the mutation profiles of conventional colorectal adenomas (CNADs) across stages of progression towards early carcinoma. DNA was isolated from 17 invasive adenocarcinomas (ACs) and 58 large CNADs, including 19 with low-grade dysplasia (LGD), 21 with LGD adjacent to areas of high-grade dysplasia and/or carcinoma (LGD-H), and 28 with high-grade dysplasia (HGD). Ion AmpliSeq Comprehensive Cancer Panel libraries were prepared and sequenced on the Ion Proton. We identified 956 unique allelic variants; of these, 499 were considered nonsynonymous variants. Eleven genes (APC, KRAS, SYNE1, NOTCH4, BLNK, FBXW7, GNAS, KMT2D, TAF1L, TCF7L2, and TP53) were mutated in at least 15% of all samples. Out of frequently mutated genes, TP53 and BCL2 had a consistent trend in mutation prevalence towards malignancy, while two other genes (HNF1A and FBXW7) exhibited the opposite trend. HGD adenomas had significantly higher mutation rates than LGD adenomas, while LGD-H adenomas exhibited mutation frequencies similar to those of LGD adenomas. A significant increase in copy number variant frequency was observed from LGD through HGD to malignant samples. The profiling of advanced CNADs demonstrated variations in mutation patterns among colorectal premalignancies. Only limited numbers of genes were repeatedly mutated while the majority were altered in single cases. Most genetic alterations in adenomas can be considered early contributors to colorectal carcinogenesis.

Predicting advanced neoplasia at colonoscopy in a diverse population with the National Cancer Institute colorectal cancer risk-assessment tool

BACKGROUND

Tailoring screening to colorectal cancer (CRC) risk could improve screening effectiveness. Most CRCs arise from advanced neoplasia (AN) that dwells for years. To date, no available colorectal neoplasia risk score has been validated externally in a diverse population. The authors explored whether the National Cancer Institute (NCI) CRC risk-assessment tool, which was developed to predict future CRC risk, could predict current AN prevalence in a diverse population, thereby allowing its use in risk stratification for screening.

METHODS

This was a prospective examination of the relation between predicted 10-year CRC risk and the prevalence of AN, defined as advanced or multiple (≥3 adenomatous, ≥5 serrated) adenomatous or sessile serrated polyps, in individuals undergoing screening colonoscopy.

RESULTS

Among 509 screenees (50% women; median age, 58 years; 61% white, 5% black, 10% Hispanic, and 24% Asian), 58 (11%) had AN. The prevalence of AN increased progressively from 6% in the lowest risk-score quintile to 17% in the highest risk-score quintile (P = .002). Risk-score distributions in individuals with versus without AN differed significantly (median, 1.38 [0.90-1.87] vs 1.02 [0.62-1.57], respectively; P = .003), with substantial overlap. The discriminatory accuracy of the tool was modest, with areas under the curve of 0.61 (95% confidence interval [CI], 0.54-0.69) overall, 0.59 (95% CI, 0.49-0.70) for women, and 0.63 (95% CI, 0.53-0.73) for men. The results did not change substantively when the analysis was restricted to adenomatous lesions or to screening procedures without any additional incidental indication.

CONCLUSIONS

The NCI CRC risk-assessment tool displays modest discriminatory accuracy in predicting AN at screening colonoscopy in a diverse population. This tool may aid shared decision-making in clinical practice. Cancer 2016. © 2016 American Cancer Society. Cancer 2016;122:2663-2670. © 2016 American Cancer Society.

Mucinous adenocarcinoma of the umbilicus 8 years following anterior resection for villous adenoma of the rectum

We present the case of an 80-year-old retired consultant histopathologist who presented to us with a malignant umbilical mass 8years following resection of a sigmoid adenoma. The report details initial investigation and management of the umbilical mass and the subsequently discovered pelvic recurrence. Our conclusions of its origin, as a malignant transformation due to seeding of the original sigmoid adenoma, show the slow progression of some colorectal tumours; and the importance of obtaining a complete specimen intra-operatively.

Advances in understanding the relationship between CD24 and colorectal cancer

Colorectal cancer (CRC) is the third cause of cancer-related morbidity and mortality in America. In China and other Asian countries, an increasingly westernized diet has led to a high incidence of CRC. There is currently an urgent demand for the discovery of novel biomarkers for CRC prognostic evaluation and molecular targeted therapies. CD24 is a mucin-like glycoprotein that is highly expressed on the surface of CRC cells. It may play a significant role in the multistep process of CRC carcinogenesis, invasion and metastasis and is correlated with therapeutic resistance and poor prognosis of CRC. As one of surface markers for potential cancer stem cells (CSCs), CD24 may be used as an ideal target for curative CRC therapy. In this review, we summarize the role of CD24 in CRC initiation, progression and metastasis. Moreover, we discuss the vital part of CD24 in CSC identification, isolation and complete CRC eradication.