Introduction to colorectal cancer

A systematic review of methods to estimate colorectal cancer incidence using population-based cancer registries

Background

Epidemiological studies of incidence play an essential role in quantifying disease burden, resource planning, and informing public health policies. A variety of measures for estimating cancer incidence have been used. Appropriate reporting of incidence calculations is essential to enable clear interpretation. This review uses colorectal cancer (CRC) as an exemplar to summarize and describe variation in commonly employed incidence measures and evaluate the quality of reporting incidence methods.

Methods

We searched four databases for CRC incidence studies published between January 2010 and May 2020. Two independent reviewers screened all titles and abstracts. Eligible studies were population-based cancer registry studies evaluating CRC incidence. We extracted data on study characteristics and author-defined criteria for assessing the quality of reporting incidence. We used descriptive statistics to summarize the information.

Results

This review retrieved 165 relevant articles. The age-standardized incidence rate (ASR) (80%) was the most commonly reported incidence measure, and the 2000 U.S. standard population the most commonly used reference population (39%). Slightly more than half (54%) of the studies reported CRC incidence stratified by anatomical site. The quality of reporting incidence methods was suboptimal. Of all included studies: 45 (27%) failed to report the classification system used to define CRC; 63 (38%) did not report CRC codes; and only 20 (12%) documented excluding certain CRC cases from the numerator. Concerning the denominator estimation: 61% of studies failed to state the source of population data; 24 (15%) indicated census years; 10 (6%) reported the method used to estimate yearly population counts; and only 5 (3%) explicitly explained the population size estimation procedure to calculate the overall average incidence rate. Thirty-three (20%) studies reported the confidence interval for incidence, and only 7 (4%) documented methods for dealing with missing data.

Conclusion

This review identified variations in incidence calculation and inadequate reporting of methods. We outlined recommendations to optimize incidence estimation and reporting practices. There is a need to establish clear guidelines for incidence reporting to facilitate assessment of the validity and interpretation of reported incidence.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12874-022-01632-7.

Taurine Attenuates the Hypotaurine-Induced Progression of CRC via ERK/RSK Signaling

Colorectal cancer (CRC) is one of the most common malignant tumors, and previous metabolomics work has demonstrated great promise in identifying specific small molecules of tumor phenotype. In the present study, we analyzed the metabolites of resected tissues through gas chromatography-mass spectrometry (GC-MS), and found that the concentration of taurine in CRC tissues diminished whereas the concentration of hypotaurine increased. The results in vitro demonstrated that taurine significantly suppressed cellular proliferation, metastasis, and colony formation whereas it induced apoptosis in CRC cells. Furthermore, taurine regulated the expression levels of epithelial mesenchymal transition (EMT)-associated genes in a dose-dependent manner. Taurine also alleviated hypotaurine-induced CRC progression, which was linked to the inhibition of the ERK/RSK-signaling pathway and diminution in intracellular hypotaurine. Taurine additionally attenuated hypotaurine-induced tumor growth and metastasis in vivo. Patients with CRC exhibited lower levels of serum taurine, suggesting that taurine might be a promising biomarker reflecting a poor prognosis in CRC. Collectively, our results demonstrated that taurine-attenuated, hypotaurine-induced CRC progression provides a potential target for CRC therapy.

Evaluation of the Biological Efficiency of Silver Nanoparticles Biosynthesized Using Croton tiglium L. Seeds Extract against Azoxymethane Induced Colon Cancer in Rats

BACKGROUND

Colorectal cancer (CRC) is considered as the most common type of gastrointestinal cancers. Chemotherapy became limited due to the adverse side effects. Therefore, the most effective Croton tiglium extract was selected to be incorporated by silver nanoparticles (Ag-NPs) then evaluated against colon cancer induced by azoxymethane (AOM) in rats.

METHODS

Different hematological and biochemical measurements were quantified in addition to markers of oxidative stress. Specific tumor and inflammatory markers were assayed. Colonic tissues were examined histopathologically in addition to immunohistochemistry (IHC). Native proteins and isoenzymes patterns were electrophoretically assayed beside expression of Tumor Protein P53 (TP53) and Adenomatous Polyposis Coli (APC) genes in colonic tissues.

RESULTS

It was found that AOM caused significant (P≤0.05) elevation in the hematological and biochemical measurements. C. tiglium nano-extract restored these measurements to normalcy. Tumor and inflammatory markers elevated significantly (P≤0.05) in sera of AOM induced colon cancer group in addition to increasing peroxidation products with decline in antioxidant enzymes activities in colon tissues. Nano-extract restored these measurements to normalcy in post-treated group. Histopathological study revealed that nano-extract minimized severity of inflammatory reactions in all nano-extract treated groups and prevented  anti-Keratin 20 antibody expression in post-treated group. The lowest similarity index (SI%) values were noticed with electrophoretic protein (SI=71.43%), lipid (SI=0.00%) and calcium (SI=75.00%) moieties of protein patterns, catalase (SI=85.71%), peroxidase (SI=85.71%), α-esterase (SI=50.00%) and β-esterase (SI=50.00%) isoenzymes in colon cancer group. Furthermore, AOM altered the relative quantities of total native bands. The nano-extract prevented the alterations that occurred qualitatively in nano-extract post-treated group and quantitatively in all nano-extract treated groups. Levels of TP53 and APC gene expression increased in AOM injected group and nano-extract restored their levels to normalcy in the post-treated group.

CONCLUSION

C. tiglium nano-extract exhibited ameliorative effect against the biochemical and molecular alterations induced by AOM in nano-extract post-treated group.

Stearoyl-CoA desaturase-1 promotes colorectal cancer metastasis in response to glucose by suppressing PTEN

BACKGROUND

Diabetic patients have a higher risk factor for colorectal cancer (CRC) metastasis. Stearoyl-CoA desaturase 1 (SCD1), the main enzyme responsible for producing monounsaturated fatty acids(MUFA) from saturated fatty acids, is frequently deregulated in both diabetes and CRC. The function and mechanism of SCD1 in metastasis of CRC and its relevance to glucose remains largely unknown.

METHODS

SCD1 expression levels were analyzed in human CRC tissues and the Cancer Browser database ( https://genome-cancer.ucsc.edu/ ). CRC cell lines stably transfected with SCD1 shRNAs or vector were established to investigate the role of SCD1 in modulating migration and invasion of CRC cells. A glucose concentration gradient was set to investigate regulation of SCD1 in CRC relevant to diabetic conditions.

RESULTS

The clinical data analysis showed high expression of SCD1 in CRC tissues with a negative correlation with the prognosis of CRC. In vitro experiments revealed that SCD1 increased CRC progression through promoting epithelial-mesenchymal transition (EMT). Lipidomic analysis demonstrated that SCD1 increased MUFA levels and MUFA administration could rescue migration and invasion defect of CRC cells induced by SCD1 knockdown. Furthermore, SCD1-mediated progression of CRC was promoted by carbohydrate response-element binding protein (ChREBP) in response to high glucose. Mechanistically, hyperglycemia-SCD1-MUFA induced CRC cell migration and invasion by regulating PTEN.

CONCLUSIONS

Our findings show that SCD1 promotes metastasis of CRC cells through MUFA production and suppressing PTEN in response to glucose, which may be a novel mechanism for diabetes-induced CRC metastasis.

Long non-coding RNA TUG1 promotes colorectal cancer metastasis via EMT pathway

Colorectal cancer (CRC) is the third most common malignancy in developed countries, and its incidence rate has been continuously increasing in developing countries over the past few decades. Taurine-upregulated gene 1 (TUG1) plays an important role in signal transduction, regulation of cell morphology, migration, proliferation and apoptosis. The aim of the present study was to evaluate the role of TUG1 in CRC, and whether knockdown of TUG1 expression could affect cell proliferation, migration and invasion of CRC cell lines. Here, we reported that TUG1 was upregulated in CRC. Further experiments revealed that TUG1 knockdown significantly inhibited cell proliferation, migration and invasion of CRC in vitro. Above all, knockdown of TUG1 may represent a rational therapeutic strategy for CRC patients in future.

Long non-coding RNA SPRY4-IT1 pormotes colorectal cancer metastasis by regulate epithelial-mesenchymal transition

Colorectal cancer (CRC) remains one of the most common cancers worldwide. Increasing evidence indicates that SPRY4 intronic transcript 1 (SPRY4-IT1) regulate cell growth, differentiation, apoptosis, and cancer progression. However, the expression and function of SPRY4-IT1 in the progression of CRC remains largely unknown. Here, we reported that SPRY4-IT1 was upregulated in CRC. Increased SPRY4-IT1 expression in CRC was associated with larger tumor size and higher clinical stage. In vitro experiments revealed that SPRY4-IT1 knockdown significantly inhibited CRC cell proliferation by causing G1 arrest and promoting apoptosis, whereas SPRY4-IT1 overexpression promoted cell proliferation. Further functional assays indicated that SPRY4-IT1 overexpression significantly promoted cell migration and invasion by regulate the epithelial-mesenchymal transition (EMT). Taken together, our study demonstrates that SPRY4-IT1 could act as a functional oncogene in CRC, as well as a potential therapeutic target to inhibit CRC metastasis.

Overexpressed transcription factor FOXM1 contributes to the progression of colorectal cancer

Forkhead box M1 (FOXM1) is a characteristic proliferation‑associated transcription factor, which is overexpressed in various types of human cancer. The aim of the present study was to determine the expression of FOXM1 in a large collection of colorectal cancer (CRC) samples. Between March 2012 and January 2014, 96 patients with histologically diagnosed CRC were recruited into the current study. Using immunohistochemistry, reverse transcription‑quantitative polymerase chain reaction and western blotting, mRNA and protein expression levels of FOXM1 in CRC tissue samples were determined. The function of FOXM1 in the CRC cells was evaluated by small interfering RNA‑mediated depletion of FOXM1, followed by analyses of cell proliferation and invasion. High levels of staining for FOXM1 were observed in significantly more CRC tissue samples: 85.42% (82/96) of CRC tissue samples compared with 18.75% (18/96) of adjacent normal mucosa tissue samples. Silencing FOXM1 inhibited the proliferation of LoVo cells, which express a relatively high level of FOXM1, and the invasion and migration of LoVo cells were also markedly suppressed. The data from the present study suggested that the pathogenesis of human CRC may be mediated by FOXM1, and that FOXM1 inhibition may provide a promising therapeutic strategy for CRC.

Mass Spectrometry-Based N-Glycomics of Colorectal Cancer

Colorectal cancer (CRC) is one of the most prevalent cancers worldwide. An increased molecular understanding of the CRC pathology is warranted to gain insights into the underlying molecular and cellular mechanisms of the disease. Altered protein glycosylation patterns are associated with most diseases including malignant transformation. Recent advances in mass spectrometry and bioinformatics have accelerated glycomics research and present a new paradigm for cancer biomarker discovery. Mass spectrometry (MS)-based glycoproteomics and glycomics, therefore, hold considerable promise to improve the discovery of novel biomarkers with utility in disease diagnosis and therapy. This review focuses on the emerging field of glycomics to present a comprehensive review of advances in technologies and their application in studies aimed at discovering novel glycan-based biomarkers. We will also discuss some of the challenges associated with using glycans as biomarkers.

Overexpression of forkhead box protein M1 (FOXM1) plays a critical role in colorectal cancer

BACKGROUND

The forkhead box M1 (FOXM1), an important regulator of cell differentiation and proliferation, is overexpressed in a number of aggressive human carcinomas. However, the clinical significance of FOXM1 signaling in human colorectal cancer (CRC) pathogenesis remains unknown. The aim of this study was to evaluate the role of FOXM1 in CRC tumorigenesis.

METHODS

We investigated FOXM1 expression in 103 cases of primary CRC and matched normal tissue specimens and explored the underlying mechanisms of altered FOXM1 expression and the impact of this altered expression on CRC proliferation and metastasis using in vitro models of CRC.

RESULTS

The results showed that high expression of FOXM1 staining was 85.44% (88/103) in 103 cases of CRC and 20.39% (21/103) in 103 cases of adjacent non-cancerous tissue samples; the difference of FOXM1 expression between two groups was statistically significant (P < 0.001). Silencing of FOXM1 inhibited the proliferation of CRC cells, and the invasion and migration of CRC cells were distinctly suppressed. Furthermore, FOXM1 knockdown led to substantial reductions in VEGF-A levels in CRC cell lines.

CONCLUSIONS

Our data suggest that the pathogenesis of CRC maybe mediated by FOXM1, and FOXM1 could represent selective targets for the molecularly targeted treatments of CRC.

Octamer transcription factor 1 mediates epithelial-mesenchymal transition in colorectal cancer

Colorectal cancer (CRC) is one of the most common cancer types worldwide. Octamer transcription factor 1 (OCT1) is associated with tumor progression and a poor patient survival rate. However, little is known regarding the effect of OCT1 in CRC. Moreover, because the epithelial-to-mesenchymal transition (EMT) is a key player in metastasis, whether OCT1 induces EMT in CRC remains unclear. In the present study, we investigate the role of OCT1 in CRC and its expression pattern and clinical significance. The expression of OCT1 in CRC tissues and the adjacent noncancerous tissues was detected using quantitative real-time PCR (QRT-PCR), Western blot, and immunohistochemistry analyses. In addition, silencing of OCT1 with small interfering RNA (siRNA) was performed in CRC cell lines, and the impact on proliferation, migration, and the EMT marker of CRC was analyzed. Our results found that OCT1 levels were significant higher in CRC tissues compared with the adjacent noncancerous tissues. Furthermore, OCT1 siRNA significantly reduced the proliferation rate of SW620 and LoVo cells, inhibited the migration and invasion, and could reverse EMT in these two CRC cells, indicating that OCT1 plays a critical role in CRC progression.

Sleep, immunity and inflammation in gastrointestinal disorders

Sleep disorders have become a global issue, and discovering their causes and consequences are the focus of many research endeavors. An estimated 70 million Americans suffer from some form of sleep disorder. Certain sleep disorders have been shown to cause neurocognitive impairment such as decreased cognitive ability, slower response times and performance detriments. Recent research suggests that individuals with sleep abnormalities are also at greater risk of serious adverse health, economic consequences, and most importantly increased all-cause mortality. Several research studies support the associations among sleep, immune function and inflammation. Here, we review the current research linking sleep, immune function, and gastrointestinal diseases and discuss the interdependent relationship between sleep and these gastrointestinal disorders. Different physiologic processes including immune system and inflammatory cytokines help regulate the sleep. The inflammatory cytokines such as tumor necrosis factor, interleukin-1 (IL-1), and IL-6 have been shown to be a significant contributor of sleep disturbances. On the other hand, sleep disturbances such as sleep deprivation have been shown to up regulate these inflammatory cytokines. Alterations in these cytokine levels have been demonstrated in certain gastrointestinal diseases such as inflammatory bowel disease, gastro-esophageal reflux, liver disorders and colorectal cancer. In turn, abnormal sleep brought on by these diseases is shown to contribute to the severity of these same gastrointestinal diseases. Knowledge of these relationships will allow gastroenterologists a great opportunity to enhance the care of their patients.

FOXM1 expression correlates with tumor invasion and a poor prognosis of colorectal cancer

FOXM1, a member of the Forkhead Box (Fox) family of transcription factors, plays a critical role in tumor development and metastasis. The aim of this study was to elucidate its role in colorectal cancer (CRC), particularly prognosis and metastasis. Semi-quantitative RT-PCR and Western blot assays were used to measure the expression levels of FOXM1 mRNA and protein in 15 CRC and adjacent normal mucosa tissues. Immunohistochemical assay was performed to detect FOXM1 protein expression in 112 CRC tissues and further determine its clinicopathological and prognostic significance. RNA interference (RNAi) was used to knockdown endogenous FOXM1 expression in CRC cell lines and to analyze the effects of FOXM1 knockdown on migration and invasion of CRC cells. The relative expression levels of FOXM1 mRNA and protein were significantly higher in CRC tissues than in adjacent normal mucosa tissues (P<0.01). In addition, the immunostaining of FOXM1 protein was stronger in CRC tissues than in adjacent normal mucosa tissues. By statistical analysis, we showed that high FOXM1 expression was closely correlated with the presence of lymph node metastasis, incidence of liver metastasis, and advanced TNM stage. Moreover, the cumulative 5-year survival rate of CRC patients with high FOXM1 expression was lower than that of those with low FOXM1 expression (P=0.0047). Multivariate analysis showed that the status of FOXM1 expression was an independent prognostic factor for CRC patients (P=0.025). Furthermore, RNAi-mediated FOXM1 knockdown could significantly inhibit growth, migration and invasion of CRC cells. Our results showed that FOXM1 over-expression is a molecular marker predicting increased invasive/metastatic potential of CRC and a poorer prognosis.

Overexpression of survivin is correlated with increased invasion and metastasis of colorectal cancer

BACKGROUND

The aim of this study was to investigate the association of survivin expression with metastasis of colorectal cancer (CRC).

METHODS

RT-PCR and Western blot assays were performed to detect survivin expression in CRC cells and normal intestinal epithelial cell. The expression of survivin gene was also detected in 15 CRC tissues, surrounding and adjacent colon tissues. Moreover, survivin expression in 48 CRC tissues with or without lymph node metastasis was analyzed. Multivariate analysis for lymph node metastasis was performed using logistic regression model. RNA interference was used to inhibit survivin expression in CRC cells and analyze its effect on invasion and metastasis of CRC cells.

RESULTS

The expression levels of survivin mRNA and protein were higher in CRC cells than in normal intestinal epithelial cell line. The average levels of survivin mRNA and protein were higher in CRC tissues than surrounding or adjacent colon tissues (P < 0.05). High survivin expression was an independent factor for predicting lymph node metastasis of CRC (P = 0.043). RNAi-mediated survivin knockdown could significantly inhibit in vitro invasion and in vivo metastasis of CRC cells, which might be inactivation of matrix metalloproteinases.

CONCLUSION

Targeting survivin will be a potential strategy to suppress metastasis of CRC.

Inhibitory effect of morin on DMH-induced biochemical changes and aberrant crypt foci formation in experimental colon carcinogenesis

Morin is a flavonoid present in fruits and Chinese herbs, exhibits various beneficial biological activities. There are numerous evidence suggesting that total dietary fat intake is generally associated with early promotion of colon cancer, the alterations in the lipid profile is important for malignant transformation and tumor development and carbohydrate moieties of glycoproteins reflect the stage of cancer. Aberrant crypt foci (ACF) consisting of morphologically irregular crypts, are thought to be precancerous lesions for colon cancer. Our aim was to study the inhibitory effect morin on aberrant crypt foci and alterations in the levels of lipids, and glycoconjugates in experimental rat colon cancer. Group 1 served as control, groups 2 and 4 received 50mg/kg b.w. morin orally everyday for 30 weeks. Groups 3 and 4 were given subcutaneous injection of 1,2-dimethylhydrazine (DMH) 20mg/kg b.w. for the first 15 weeks. Administration of morin at the dose of 50mg/kg b.w., significantly suppressed the formation of ACF its multiplicity and lowered levels of serum and tissue lipids, cholesterol-phospholipid ratio, glycoconjugate and also increased the activity of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG CoA reductase). These results indicate that morin has a protective effect against DMH-induced colon carcinogenesis.

Survivin: a potential prognostic marker and chemoradiotherapeutic target for colorectal cancer

OBJECTIVE

The aim of our study was to explore the expression of survivin gene in colorectal cancer (CRC) and its possibility as a molecular target for CRC chemoradiotherapy.

MATERIALS AND METHODS

Immunohistochemistry was performed to detect the expression of survivin in 68 CRC specimens. The correlations between survivin expression and clinicopathological factors and prognosis were evaluated. RNA interference was employed to downregulate survivin expression. The effects of survivin downregulation on chemoradiotherapy of CRC cells were evaluated.

RESULTS

The staining of survivin protein was strongly positive in the cytoplasm of CRC cells. Its expression was significantly correlated with tumor differentiation, Duke's stage, lymph node metastasis. Moreover, the elevated survivin expression was an independent factor for predicting the prognosis of CRC patients. Survivin downregulation could also enhance chemosensitivity or radiosensitivity of colorectal cells.

CONCLUSIONS

Survivin might be an independent prognostic factor and a potential target for the chemoradiotherapy of CRC patients.

Self-reported information on the diagnosis of colorectal cancer was reliable but not necessarily valid

OBJECTIVE

Self-report is commonly used in epidemiologic studies; however, few data exist on the reliability and validity of this method for eliciting information related to the diagnosis of colorectal cancer. We examined the test-retest reliability and validity of colorectal cancer patients reporting on the process of their diagnosis.

STUDY DESIGN AND SETTING

One hundred and sixteen participants completed two telephone interviews, 1 month apart, and 95 general practitioners (GPs) completed a written questionnaire, to elicit information relating to key elements of the process of diagnosis of colorectal cancer.

RESULTS

Acute symptoms such as rectal bleeding had higher reliability and validity than more general symptoms. Colonoscopy was the most accurately recalled diagnostic test. Recall of diagnosis date, and date of colonoscopy, had high test-retest reliability. There were considerable differences between dates of diagnostic tests given by participants and GPs, but there was no evidence of a bias in a particular direction. Accuracy of recall did not diminish as time from diagnosis increased.

CONCLUSION

This study confirms that self-reported symptoms, tests, and dates in the colorectal cancer diagnostic pathway are generally reliable; however, the validity of reported symptoms and tests can be moderate to poor.

Plasma lysophosphatidylcholine levels: potential biomarkers for colorectal cancer

PURPOSE

Plasma levels of lysophospholipids were evaluated as potential biomarkers for colorectal cancer (CRC), where a highly reliable and minimally invasive blood test is lacking.

PATIENTS AND METHODS

Patients with CRC (n = 133) and control subjects (n = 125) were recruited through the Cleveland Clinic. Preoperative plasma samples were analyzed for lysophospholipid levels using liquid chromatography mass spectrometry in a blinded fashion. Participants were randomly divided in a 2:1 ratio into a "training set" (TS) and a "validation set" (VS). Logistic regression models were used in the TS to identify markers that best discriminated between CRC and controls. A cutoff point for the final discriminating model was developed using the receiver operating characteristic curve to achieve 95% specificity. All analyses were then independently validated in the VS.

RESULTS

Plasma levels of several lysophosphatidylcholines (LPCs), including 18:1- and 18:2-LPC, were significantly decreased in CRC patients compared with controls (P < .001). A model based on total saturated LPC and the difference between the proportional amounts of 18:2-LPC and 18:1-LPC in the unsaturated LPC fraction was derived from the TS. This model achieved a sensitivity and specificity of 82% and 93%, respectively, in the VS. Overall, 118 (94%) of 125 control subjects and 113 (85%) of 133 CRC cases were correctly identified, including eight (89%) of nine CRC cases with stage T1 disease.

CONCLUSION

Percentage of 18:1-LPC or 18:2-LPC plasma levels compared with total saturated LPC levels, either individually or in combination, may represent potential biomarkers for CRC.

Effects of TNP-470 on proliferation and apoptosis in human colon cancer xenografts in nude mice

AIM: To study the effect of TNP-470 on cell growth, proliferation and apoptosis in human colon cancer xenografts in nude mice.

METHODS: Human colon cancer xenografts were transplanted into 20 nude mice. Mice were randomly divided into two groups. TNP-470 treated group received TNP-470 (30 mg/kg, s.c) every other day and the control group received a sham injection of same volume saline solution. They were sacrificed after 4 wk and their tumors were processed for histological examination. The expression of proliferating cell nuclear antigen (PCNA) in tumors was detected using immunohistochemical method with image analysis, and apoptosis in tumor cells was measured by TdT-mediated biotinyated-dUTP nick end labeling (TUNEL) staining.

RESULTS: Comparing with controls, tumor growth was significantly inhibited in TNP-470 treated group, the inhibitory rate being 54.4%. Expression of PCNA in tumors of TNP-470 treated group (PI 54.32 ± 11.47) was significantly lower than that of control group (PI 88.54 ± 12.36), P < 0.01. Apoptosis index (AI) of TNP-470 treated group (18.95 ± 1.71) was significantly higher than that of control group (7.26 ± 1.44), P < 0.001, typical morphological change of apoptosis in tumor cells was observed in TNP-470 treated group.

CONCLUSION: Besides the anti-angiogenic effects, TNP-470 can inhibit tumor growth by inhibiting the proliferation and inducing apoptosis of tumor cells.