Increasing incidence of colorectal cancer in Asia: implications for screening

The comparison of the clinical manifestations and risk factors of colorectal cancer and adenomas: results from a colonoscopy-based study in southern Chinese

BACKGROUND AND AIMS

Colorectal cancer (CRC) is one of the most common gastrointestinal tumors in the world. This study aimed to compare the clinical manifestations and risk factors of CRC and adenomas in native patients of Guangzhou.

METHODS

Patients who underwent colonoscopy for the first time at Nanfang Hospital between July 2008 and July 2009 were recruited. Data on demographic information, main clinical manifestations, results of endoscopies and pathology, and possible risk factors of colorectal tumor were collected. Chi-square test and logistic regression were used to compare the clinical characteristics and risk factors for CRC and adenomas.

RESULTS

Hematochezia and body weight loss were more frequent in proximal and distal CRC groups, respectively (P ≤  0.05). Older age [odds ratio (OR), 1.079; 95% confidence interval (CI), 1.065-1.093], smoking status (OR, 1.712; 95% CI, 1.158-2.531), BMI =18.5-24.9 and  ≥ 25.0 (OR, 2.384; 95% CI, 1.250-4.549; OR, 2.162; 95% CI, 1.044-4.478, respectively) were significant risk factors for advanced adenoma, while female (OR, 0.638; 95% CI, 0.429-0.949) and using aspirin (OR, 0.188; 95% CI, 0.042-0.845) were significant protective factors. Hyperlipemia (OR, 0.109; 95% CI, 0.013-0.886) was identified as a protective factor for proximal CRC. Smoking (OR, 1.717; 95% CI, 1.093-2.696), drinking (OR, 1.817; 95% CI, 1.145-2.883), DM history (OR, 2.204; 95% CI, 1.044-4.652) were identified as independent risk factors for distal CRC, and using aspirin (OR, 0.190; 95% CI, 0.043-0.840) was a protective factor. Drinking (OR, 3.288; 95% CI, 1.546-6.994; OR, 1.862; 95% CI, 1.037-3.343, respectively) was an independent risk factor for both poorly to moderately differentiated CRC and well-differentiated CRC. Besides, DM (OR, 3.761; 95% CI, 1.615-8.762) and hypertension (OR, 0.384; 95% CI, 0.178-0.828) were identified as independent risk factor and protective factor for well-differentiated CRC, respectively.

CONCLUSIONS

Hematochezia and body weight loss were representative manifestations for distal and proximal CRC, respectively. For southern Chinese the most important influential factors for colorectal tumor are age, smoking, drinking, nutritional state, DM, hypertension, and the use of aspirin.

Association between colorectal adenoma and coronary atherosclerosis detected by CT coronary angiography in Korean men; a cross-sectional study

BACKGROUND

Colorectal adenoma and coronary artery disease (CAD) appear to share common risk factors, such as male gender, diabetes mellitus, smoking, and obesity. We investigated the relationship between colorectal adenoma and coronary atherosclerosis, as a risk factor for colorectal adenoma.

METHODS

A cross-sectional study was conducted on Korean men who presented for a health check-up. The subjects were 488 men (217 colorectal adenoma and 271 normal colonoscopic findings) who underwent colonoscopy and coronary computed tomography angiography (CTA) on the same day as a screening examination. Advanced colonic lesion was defined as a presence of adenoma with villous component, high-grade dysplasia, and/or with size of ≥1 cm. CTA findings were classified as normal, mild (low-grade atherosclerosis or <50% stenosis), and significant CAD (≥50% stenosis). Abnormal CTA findings included mild and significant CAD.

RESULTS

Patients with abnormal CTA findings were more likely to have colorectal adenoma compared with those with normal CTA findings (P < 0.005). Furthermore, presence of advanced adenoma was significantly associated with significant CAD (P < 0.01). On multivariate analyses, abnormal CTA findings (OR = 1.66, 95% CI: 1.14-2.41, P < 0.01) and significant CAD (OR = 1.96, 95% CI: 1.15-3.35, P < 0.05) were found to be independent risk factors for colorectal adenoma after adjusting for age, current smoking, and metabolic syndrome.

CONCLUSIONS

In this study, in the population who underwent CTA and colonoscopy for health check-up, prevalence of colorectal adenoma was greater in subjects with low-grade coronary atherosclerosis or significant CAD. The presence of advanced adenoma was significantly associated with significant CAD.

L1, β-catenin, and E-cadherin expression in patients with colorectal cancer: correlation with clinicopathologic features and its prognostic significance

OBJECTIVE

Currently, there are no clinically used/routine biomarkers that accurately predict whether colorectal cancer (CRC) patients will or will not respond to adjuvant chemotherapy. The aim of this study was to investigate L1, β-catenin, and E-cadherin expression in patients with CRC and their relationship to tumor progression, and to identify patients who will respond to chemotherapy.

METHODS

A total of 142 patients who underwent surgical treatment for CRC were chosen retrospectively. The samples from these patients were analyzed by immunohistochemistry. SPSS-14 program package was used for statistical calculation.

RESULTS

Expression of L1, β-catenin, and E-cadherin were found to be strongly associated with invasion and metastasis of CRC. Cox multivariate analysis results indicated that L1 expression and stage of Dukes could be considered as the independent prognostic factors for survival. Furthermore, our study found that the 5-year survival rate was the significantly associated with the expression of L1, β-catenin (normal and ectopic expression), and E-cadherin for Dukes' stage B (P < 0.01) patients. However, no such result was found for Dukes' stage A (P > 0.05) and C (P > 0.05) patients.

CONCLUSION

Our study provided reference for identifying patients who need adjuvant chemotherapy. L1, β-catenin, and E-cadherin could be considered as biomarkers to predict whether CRC patients will or will not respond to adjuvant chemotherapy.

Up-regulation of hnRNP A1, Ezrin, tubulin β-2C and Annexin A1 in sentinel lymph nodes of colorectal cancer

AIM: To investigate the early metastasis-associated proteins in sentinel lymph node micrometastasis (SLNMM) of colorectal cancer (CRC) through comparative proteome.

METHODS: Hydrophobic protein samples were extracted from individual-matched normal lymph nodes (NLN) and SLNMM of CRC. Differentially expressed protein spots were detected by two-dimensional electrophoresis and image analysis, and subsequently identified by matrix assisted laser desorption/ionization-time of flight mass spectrometry-mass spectrometry and Western blotting, respectively.

RESULTS: Forty proteins were differentially expressed in NLN and SLNMM, and 4 metastasis-concerned proteins highly expressed in SLNMM were identified to be hnRNP A1, Ezrin, tubulin β-2C and Annexin A1. Further immunohistochemistry staining of these four proteins showed their clinicopathological characteristics in lymph node metastasis of CRC.

CONCLUSION: Variations of hydrophobic protein expression in NLN and SLNMM of CRC and increased expression of hnRNP A1, Ezrin, tubulin β-2C and Annexin A1 in SLNMM suggest a significantly elevated early CRC metastasis.

Distribution trends of colorectal adenoma and cancer: a colonoscopy database analysis of 11,025 Chinese patients

BACKGROUND AND AIM

A left-to-right shift of colorectal cancer (CRC) has been reported in Western studies. However, few Asian studies have investigated the anatomic distribution of colorectal adenoma and CRC. We aimed to describe the time trends in the distribution of colorectal adenoma and CRC in a Chinese population.

METHODS

A colonoscopy database was reviewed, and all consecutive patients with lower gastrointestinal symptoms who underwent colonoscopy from 1998 to 2009 were identified. Data, including patients' sex, age, symptoms, and the number and anatomic locations of colorectal adenoma and CRC, were documented.

RESULTS

A total of 11,025 patients were included in the final analysis; 1012 and 363 patients were diagnosed with colorectal adenoma and CRC, respectively. Overall, there were more distal than proximal adenomas (54.4% vs 37.9%), and the proportion of proximal adenomas remained stable from 1998-2006 to 2007-2009 (38.2% vs 37.6%). Similarly, there were more distal than proximal CRC (56.5% vs 42.4%), and the proportion of proximal CRC declined from 45.8% in 1998-2006 to 38.4% in 2007-2009. Colorectal adenoma and CRC were equally distributed among both sexes. For elderly patients (> 50 years), there was a non-significant trend towards more proximal adenoma and CRC.

CONCLUSIONS

The present study suggests no distal-to-proximal shift of colorectal adenoma and CRC among the Chinese population in Shanghai over the past 12 years. The distribution pattern of colorectal adenoma and CRC of Chinese patients is different from that of Western patients, who had more colorectal lesions located in the distal part.

A case-controlled validation study of a blood-based seven-gene biomarker panel for colorectal cancer in Malaysia

BACKGROUND

Colorectal cancer (CRC) screening is key to CRC prevention and mortality reduction, but patient compliance with CRC screening is low. We previously reported a blood-based test for CRC that utilizes a seven-gene panel of biomarkers. The test is currently utilized clinically in North America for CRC risk stratification in the average-risk North American population in order to improve screening compliance and to enhance clinical decision making.

METHODS

In this study, conducted in Malaysia, we evaluated the seven-gene biomarker panel validated in a North American population using blood samples collected from local patients. The panel employs quantitative RT-PCR (qRT-PCR) to analyze gene expression of the seven biomarkers (ANXA3, CLEC4D, TNFAIP6, LMNB1, PRRG4, VNN1 and IL2RB) that are differentially expressed in CRC patients as compared with controls. Blood samples from 210 patients (99 CRC and 111 controls) were collected, and total blood RNA was isolated and subjected to quantitative RT-PCR and data analysis.

RESULTS

The logistic regression analysis of seven-gene panel has an area under the curve (AUC) of 0.76 (95% confidence interval: 0.70 to 0.82), 77% specificity, 61% sensitivity and 70% accuracy, comparable to the data obtained from the North American investigation of the same biomarker panel.

CONCLUSIONS

Our results independently confirm the results of the study conducted in North America and demonstrate the ability of the seven biomarker panel to discriminate CRC from controls in blood samples drawn from a Malaysian population.

Biomarkers for colorectal cancer

Colorectal cancer (CRC) is the third most common epithelial malignancy in the world. Since CRC develops slowly from removable precancerous lesions, detection of the lesion at an early stage by regular health examinations can reduce the incidence and mortality of this malignancy. Colonoscopy significantly improves the detection rate of CRC, but the examination is expensive and inconvenient. Therefore, we need novel biomarkers that are non-invasive to enable us to detect CRC quite early. A number of validation studies have been conducted to evaluate genetic, epigenetic or protein markers for identification in the stool and/or serum. Currently, the fecal occult blood test is the most widely used method of screening for CRC. However, advances in genomics and proteomics will lead to the discovery of novel non-invasive biomarkers.

Prevalence and risk of colorectal neoplasms in asymptomatic, average-risk screenees 40 to 49 years of age

BACKGROUND

A paucity of information exists regarding colorectal neoplasm in asymptomatic, average-risk individuals 40 to 49 years of age.

OBJECTIVE

To evaluate the prevalence and risk factors of colorectal neoplasms in those in their 40s.

DESIGN

Cross-sectional study.

SETTING

Results offered to subjects of a health care provider that offers screening services as part of an employer-provided wellness program.

PATIENTS

A consecutive series of 1761 asymptomatic, average-risk screenees 40 to 59 years of age.

INTERVENTION

First screening colonoscopy.

RESULTS

The prevalence of overall colorectal neoplasm in subjects of ages 40 to 44 years, 45 to 49 years, 50 to 54 years, and 55 to 59 years increased significantly with increasing age (13.7%, 20.2%, 21.0%, and 23.8%, respectively; P < .001). The prevalence of advanced adenomas in subjects of ages 40 to 44 years, 45 to 49 years, 50 to 54 years, and 55 to 59 years increased significantly with age (1.9%, 3.0%, 3.2%, and 5.9%, respectively; P = .004). Multivariate analysis of data from the 40- to 49-year age group identified an increased risk of colorectal neoplasm associated with ages 45 years and older (odds ratio [OR], 1.68; 95% CI, 1.20-2.35), male sex (OR, 1.76; 95% CI, 1.15-2.69), presence of abdominal obesity (OR, 1.57; 95% CI, 1.12-2.21), and metabolic syndrome (OR, 1.56; 95% CI, 1.03-2.35), whereas for advanced adenomas, abdominal obesity (OR, 2.37; 95% CI, 1.06-5.27) and metabolic syndrome (OR, 2.83; 95% CI, 1.23-6.53) were the independent risk factors.

LIMITATIONS

Single-center study and the cohort composed of ethnic Korean subjects who lived in the same geographic region.

CONCLUSION

In average-risk individuals 40 to 49 years of age, men with abdominal obesity or metabolic syndrome might benefit from screening colonoscopy starting at 45 years of age to detect colorectal neoplasm.

PTCH1, a receptor of Hedgehog signaling pathway, is correlated with metastatic potential of colorectal cancer

BACKGROUND

Approximately 90% of colorectal cancer (CRC) deaths arise from the metastatic dissemination of primary tumors. It is difficult to predict metastasis of colorectal cancer, especially for patients with the same pathological subtype and differentiation. AIMS. To identify biomarkers for predicting CRC metastasis.

PATIENTS AND METHODS

We collected 19 primary tumors of CRC with identical pathological subtype, differentiation, and comparable Dukes' stages from patients with matched age and gender but completely different prognosis. Patients were divided into one high-risk and one low-risk group for metastasis. The expression levels of SHH, PTCH1, and sFRP1, which are components of the Hedgehog signaling pathway, were determined by real-time reverse transcription polymerase chain reaction (RT-PCR). To investigate further the correlation between expression level of PTCH1 and metastatic potential of CRC cells, we compared the mRNA and protein levels of the PTCH1 gene in LoVo cells with high metastatic potential and in HT-29, SW480, and SW620 cells with low metastatic potential by RT-PCR and flow cytometry.

RESULTS

We found that tumor tissues in the high-risk group for metastasis expressed lower levels of PTCH1 mRNA than did those in the low-risk group. Similarly, mRNA and protein levels of PTCH1 were inversely correlated with the metastatic potential of CRC cell lines. Expression levels of SHH and sFRP1 genes did not differ between the two groups.

CONCLUSION

Our data suggest that PTCH1 might be a potential biomarker that could discriminate CRC with high from that with low metastatic risk.

Advanced synchronous adenoma but not simple adenoma predicts the future development of metachronous neoplasia in patients with resected colorectal cancer

BACKGROUND

Patients with resected colorectal cancer remain at a high risk for developing metachronous neoplasia in the remnant colorectum. The aim of this study was to identify baseline clinical and colonoscopic features predictive of metachronous neoplasia after curative resection of colorectal cancer.

METHODS

The baseline clinical and colonoscopic data and follow-up details of 503 patients who had colonoscopic surveillance after curative colorectal resection between January 2000 and October 2005 in a single tertiary institution were analyzed. Univariate and multivariate analyses were done to identify risk factors for metachronous adenoma.

RESULTS

Metachronous adenomas were diagnosed in 176 patients (35.0%) and advanced adenomas in 39 (7.8%) during the follow-up period (35.7+/-20.9 mo). Among the clinical and colonoscopic factors at baseline, advanced age (> or = 60 y) (odds ratio (OR)=3.64; 95% confidence intervals (CI), 1.55-8.52), the presence of advanced synchronous adenoma (OR=4.38; 95% CI, 1.77-10.85), and longer total follow-up period (OR=1.03; 95% CI, 1.01-1.04) were independently correlated with developing advanced metachronous adenoma. Patients who had synchronous tubular adenoma without advanced features at baseline were not found to have an increased risk for future development of advanced metachronous adenoma compared with those in the synchronous adenoma-free group (OR=1.75; 95% CI, 0.69-4.43, P=0.650).

CONCLUSIONS

Our data showed that patients with advanced synchronous adenoma at baseline were identified to have an increased risk of advanced metachronous neoplasia during a longer follow-up period but those with tubular adenoma without advanced features at baseline were not.

Tian Xian Liquid (TXL) induces apoptosis in HT-29 colon cancer cell in vitro and inhibits tumor growth in vivo

Background

Tian Xian Liquid (TXL) is a Chinese medicine decoction and has been used as an anticancer dietary supplement. The present study aims to investigate the effects of TXL on the apoptosis of HT-29 cells and tumor growth in vivo.

Method

HT-29 colon cancer cells were treated with gradient dilution of TXL. The mitochondrial membrane potential was measured by JC-1 assay. The release of cytochrome c from mitochondrial and apoptosis-related proteins Bax, Bcl-2, cleaved caspase-3, 9 were examined by Western blot analysis. HT-29 cells were implanted in nude mice to examine the effects of TXL on tumor growth.

Result

TXL inhibited HT-29 xenografted model and showed a strong and dose-dependent inhibitory effect on the proliferation of HT-29 cells. Mitochondrial membrane potential was reduced by TXL at the concentration of 0.5% above. For Western blot analysis, an increase in Bax expression and a decrease in Bcl-2 expression were observed in TXL-treated cells. TXL treatment increased the protein level of cleaved casepase-3 and caspase-9, and the release of cytochrome c in cytoplasm was up-regulated as well.

Conclusion

TXL significantly inhibits cell proliferation in the HT-29 cells and HT-29 xenografted model via the mitochondrial cell death pathway.

Aberrant promoter methylation of p16 in colorectal adenocarcinoma in North Indian patients

AIM: To investigate p16 gene methylation and its expression in 30 patients with sporadic colorectal adenocarcinoma in a North Indian population.

METHODS: Methylation specific polymerase chain reaction was used to detect p16 gene methylation and immunohistochemistry was used to study the p16 expression in 30 sporadic colorectal tumors as well as adjoining and normal tissue specimens.

RESULTS: Aberrant promoter methylation of p16 gene was detected in 12 (40%) tumor specimens, whereas no promoter methylation was observed in adjoining and normal tissue. Immunohistochemistry showed expression of p16 protein in 26 (86.6%) colorectal tumors whereas complete loss of expression was seen in 4 (13.3%) and reduced expression was observed in 12 (40%) tumors. In the adjoining mucosa, expression of p16 was in 11 (36.6%) whereas no clear positivity for p16 protein was seen in normal tissue. There was a significant difference in the expression of p16 protein in tumor tissue and adjoining mucosa (P < 0.001). The methylation of the p16 gene had a significant effect on the expression of p16 protein (P = 0.021). There was a significant association of methylation of p16 gene with the tumor size (P = 0.015) and of the loss/reduced expression of p16 protein with the proximal site of the tumor (P = 0.047). Promoter methylation and expression of p16 had no relation with the survival of the patients (P > 0.05).

CONCLUSION: Our study demonstrated that promoter hypermethylation of the p16 gene results in loss/reduced expression of p16 protein and this loss/reduced expression may contribute to tumor enlargement.

Factors associated with the intention to have colorectal cancer screening in Korean adults

The purpose of this study was to investigate the factors related to screening intention in a population-based screening programme for colorectal cancer. The data were taken from the 2008 Korean National Cancer Screening Survey. We conducted a nationwide survey with trained interviewers using a questionnaire. A total of 2038 participants agreed to answer the survey. There were 955 study subjects aged ≥ 50 years in the target age group for colorectal cancer screening. Colorectal cancer screening behaviour and demographic characteristics were collected to evaluate intention for colorectal cancer screening and related factors. Descriptive statistics and multiple logistic regression were used in the analysis. The lifetime screening rate was 50.4% (50.9% for men and 49.8% for women). The screening rate with recommendation was 39.7% (39.3% for men and 40.1% of women). The odds ratios of intention to be screened increased significantly in younger subjects and those screened with double-contrast barium enema or colonoscopy. 'Without any symptoms' was reported as the most frequent reason for non-attendance or no intention to be screened. Age and recent screening methods were important factors related to intention to be screened for colorectal cancer. Further research is needed to identify remaining barriers to screening.

Adenomatous colorectal polyps in patients referred for colonoscopy in a regional hospital in Kuwait

BACKGROUND/AIM

Adenomatous colorectal polyps (ACPs) are known to be the precursor lesions for colorectal cancer. The aim of the study was to determine the prevalence, endoscopic and pathological features of ACPs in patients referred for colonoscopy.

PATIENTS AND METHODS

The endoscopic and histological reports of adult patients who underwent complete colonoscopy in the gastroenterology unit of a regional Kuwaiti hospital between January 2008 and December 2008 were retrospectively studied. The specimens of polyps were reviewed by an experienced pathologist who was blinded to the clinical or endoscopic information. Non-neoplastic polyps were not included in the analysis.

RESULTS

Of 530 eligible patients (mean age, 45 years; male-female ratio, 2:1), 54 (10%) had 103 ACPs. Of the patients with ACPs (mean age, 57 years), 43 (80%) were males and 36 (67%) were Kuwaitis. Histopathological examination of the most significant polyp in each patient revealed that 40 (74%) polyps were tubular adenomas (TAs); 11 (20%), tubulovillous (TV) adenomas; and 3 (6%), villous adenomas. High-grade dysplasia was noticed in 4 (10%) adenomas. Fifteen (2.8%) of the 530 patients had advanced ACPs. Logistic regression analysis of some variables and their association with ACPs found that age (P < 0.001; OR, 1.9; CI, 1.5-2.3), history of adenoma (P=0.001; OR, 6.4; CI, .2.1-19.4) and being Kuwaitis (P=0.029; OR, 2.1; CI, 1.1-4.1) to be independently associated with ACPs.

CONCLUSION

The most common histological type of ACPs was tubular adenoma. Advancing age, being Kuwaiti nationals and prior removal of ACPs were significantly associated with the occurrence of ACPs.

Loss of SM22 is a characteristic signature of colon carcinogenesis and its restoration suppresses colon tumorigenicity in vivo and in vitro

BACKGROUND

We previously found the down-expression of SM22 in an experimental animal model of colorectal cancer by performing a proteomic analysis. In this study, we addressed the expression and molecular mechanisms of SM22 in human colorectal cancer.

METHODS

To evaluate the expression of SM22 in colon cancers, Western blot and immunohistochemistry were performed in 13 normal, 14 adenomas, and 44 adenocarcinomas. To address the role of SM22 in colon carcinogenesis, SM22 was restored in the colon cancer cells by the transfection with the pIRES2 vector containing full-length SM22 cDNA and tested for tumorigenicity in vivo and in vitro.

RESULTS

SM22 was found to be significantly down-regulated in adenocarcinoma (58%) compared with adenoma (21.4%) and normal (15.3%). The loss of SM22 correlated with poor differentiation of tumor (P = 0.009) and lymph node metastasis (P = 0.029). Restoration of SM22 expression inhibited cell migration, colony-forming ability of cancer cells, and induced retardation of in vivo tumor growth in a xenograft model.

CONCLUSIONS

Loss of SM22 is a molecular signature of colon cancer and is closely associated with progression, differentiation, and metastasis of colon cancer. The restoration of SM22 leads to an inhibition of colon carcinogenesis in vivo and in vitro, suggesting that SM22 might potentially function as a novel tumor suppressor.

Management of liver metastases from colorectal cancer

About 50% of colorectal cancer patients develop liver metastasis, and liver resection is considered the only curative therapy. However, the rate of recurrence is high, which contributes to poor prognosis. Since surgical resection coverage has increased because of improved hepatectomy including portal vein embolization, tumors shrink because of the effectiveness of recent chemotherapy, such as FOLFOX and FOLFIRI, and it has become possible for many patients whose cancer was judged unresectable before to undergo resection. Improvement of new anticancer drugs such as molecularly targeted biologics is greatly changing therapeutic systems of metastatic colorectal cancer, and it is time for us to innovate stage IV therapy. In this report, we will review new treatment strategies for metastatic liver cancer from colorectal cancer, clinical trials of new anticancer drugs for liver metastasis, surgery and ablation as local therapy, and further clarify complex therapeutic systems for metastatic liver tumors from colorectal cancer.

Urinary metabonomic study on colorectal cancer

After our serum metabonomic study of colorectal cancer (CRC) patients recently published in J. Proteome Res., we profiled urine metabolites from the same group of CRC patients (before and after surgical operation) and 63 age-matched healthy volunteers using gas chromatography-mass spectrometry (GC-MS) in conjunction with a multivariate statistics technique. A parallel metabonomic study on a 1,2-dimethylhydrazine (DMH)-treated Sprague-Dawley rat model was also performed to identify significantly altered metabolites associated with chemically induced precancerous colorectal lesion. The orthogonal partial least-squares-discriminant analysis (OPLS-DA) models of metabonomic results demonstrated good separations between CRC patients or DMH-induced model rats and their healthy counterparts. The significantly increased tryptophan metabolism, and disturbed tricarboxylic acid (TCA) cycle and the gut microflora metabolism were observed in both the CRC patients and the rat model. The urinary metabolite profile of postoperative CRC subjects altered significantly from that of the preoperative stage. The significantly down-regulated gut microflora metabolism and TCA cycle were observed in postoperative CRC subjects, presumably due to the colon flush involved in the surgical procedure and weakened physical conditions of the patients. The expression of 5-hydroxytryptophan significantly decreased in postsurgery samples, suggesting a recovered tryptophan metabolism toward healthy state. Abnormal histamine metabolism and glutamate metabolism were found only in the urine samples of CRC patients, and the abnormal polyamine metabolism was found only in the rat urine. This study assessed the important metabonomic variations in urine associated with CRC and, therefore, provided baseline information complementary to serum/plasma and tissue metabonomics for the complete elucidation of the underlying metabolic mechanisms of CRC.

EZH2 and STAT6 expression profiles are correlated with colorectal cancer stage and prognosis

AIM: To investigate the role of enhancer of zeste homologue 2 (EZH2) and STAT6 immunohistochemistry in the evaluation of clinical stages and prognosis of colorectal cancer (CRC).

METHODS: The expression patterns were examined by immunohistochemistry in both tumor and adjacent non-neoplastic tissues of 119 CRC patients who underwent operation during the time period from 2002 to 2004.

RESULTS: The positive rates of EZH2 and STAT6 in CRC cases were 69.7% (83 of 119) and 60.5% (72 of 119), respectively, and there was significant difference when compared with tumor adjacent non-neoplastic tissues (P < 0.05). In all CRC cases, patients with EZH2-positive, or STAT6-positive expression had lower survival rates than those with EZH2-negative or STAT6-negative expression (P = 0.002 and P = 0.005, respectively). Co-expression of EZH2 and STAT6 showed significantly higher levels in CRC cases of high clinical TNM stages (P = 0.001), and the expression of STAT6 was also correlated with lymph node metastasis and distant metastasis (P = 0.001 and P = 0.016, respectively). Multivariate analysis revealed that EZH2 expression was an independent prognostic indicator of CRC (P = 0.039).

CONCLUSION: EZH2 and STAT6 expressions have significant values in distinguishing clinical stages of CRC and predicting the prognosis of the patients.

Lifestyle, occupational, and reproductive factors and risk of colorectal cancer

PURPOSE

Lifestyle factors and environmental exposures might help explain the risk of colorectal carcinoma in countries where the incidence is low, but unique patterns of young onset and a high proportion of rectal cancer exist.

METHODS

We obtained detailed lifestyle information from 421 patients with colorectal cancer and 439 hospital-controls in Egypt. Logistic regression models were computed to evaluate the risk factors of colorectal carcinoma.

RESULTS

A history of pesticide exposure and more frequently eating food directly from farms were significantly associated with a higher risk of colorectal carcinoma (odds ratio = 2.6; 95% CI = 1.1-5.9, and odds ratio = 4.6; 95% CI = 1.5-14.6, respectively). Parous women who reported 7 or more live births or breastfed for 19 months or longer per live birth had a significantly lower risk for colorectal carcinoma (odds ratio = 0.3; 95% CI = 0.2-0.7, and odds ratio = 0.2; 95% CI = 0.1-0.4, respectively). Compared with patients aged 40 years or older, industrial exposures were more common in younger patients (P = .05).

CONCLUSIONS

Agricultural and industrial exposures were associated with increased risk of colorectal carcinoma, whereas prolonged lactation and increased parity were inversely associated with colorectal carcinoma in women. Further research to elucidate the biological role of intense environmental and industrial exposures and reproductive factors including lactation may further clarify the etiology of colorectal cancer.

Expression and functional characterization of platelet-derived growth factor receptor-like gene

AIM: To investigate the role of platelet-derived growth factor receptor-like gene (PDGFRL) in the anti-cancer therapy for colorectal cancers (CRC).

METHODS: PDGFRL mRNA and protein levels were measured by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry in CRC and colorectal normal tissues. PDGFRL prokaryotic expression vector was carried out in Escherichia coli (E. coli), and purified by immobilized metal affinity chromatography. The effect of PDGFRL protein on CRC HCT-116 cells was detected by 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT), clone counting, cell cycle, and wound healing assay.

RESULTS: Both RT-PCR and immunohistochemistry showed that the expression of PDGFRL in colorectal normal tissues was higher than in cancer tissues. Recombinant pET22b-PDGFRL prokaryotic expression vector was successfully expressed in E. coli, and the target protein was expressed in the form of inclusion bodies. After purification and refolding, recombinant human PDGFRL (rhPDGFRL) could efficiently inhibit the proliferation and invasion of CRC HCT-116 cells detected by MTT, clone counting and wound healing assay. Moreover, rhPDGFRL arrested HCT-116 cell cycling at the G0/G1 phase.

CONCLUSION: PDGFRL is a potential gene for application in the anti-cancer therapy for CRC.

Impact of metastatic lymph node ratio in node-positive colorectal cancer

Colorectal cancer (CRC) is one of the most common malignant diseases in the world. Presently, the most widely used staging system for CRC is the tumor nodes metastasis classification system, which classifies patients into prognostic groups according to the depth of the primary tumor, presence of regional lymph node (LN) metastases, and evidence of distant metastatic spread. The number of LNs with confirmed metastasis is related to the severity of the disease, but this number depends on the number of LNs retrieved, which varies depending on patient age, tumor grade, surgical extent, and tumor site. Numerous studies and a recent structured review have demonstrated associated improvements in the survival of CRC patients with increasing numbers of LNs retrieved for examination. Hence, the impact of lymph node ratio (LNR), defined as the number of metastatic LNs divided by the number of LNs retrieved, has been investigated in various malignancies, including CRC. In this editorial, we review the literature demonstrating the clinicopathological significance of LNR in CRC patients. Some reports have indicated the advantage of considering the LNR compared to the number of LNs retrieved and/or LN status. When the LNR is taken into consideration for survival analysis, the number of LNs retrieved and/or the LN status is not always found to be a prognostic factor. The cut-off points for LNRs were proposed in numerous studies. However, optimal thresholds for LNRs have not yet received consensus. It is still unclear whether the LNR has more prognostic validity than N stage. For all these reasons, the potential advantages of LNRs in the staging system should be investigated in large prospective data sets.

FANCD2 mRNA overexpression is a bona fide indicator of lymph node metastasis in human colorectal cancer

BACKGROUND

Lymph node metastasis is widely accepted as one of the most important determinants of prognosis in colorectal cancer (CRC) patients. Therefore, there is an urgent need to identify molecular markers that can be used to predict lymph node metastasis.

MATERIALS AND METHODS

Candidate genes were found using LMD and cDNA microarrays in a large-scale study of CRC, followed by Penalized Canonical Correlation Analysis (PCCA). We focused on the Fanconi anemia, complementation group D2 (FANCD2) gene and evaluated FANCD2 mRNA expression in 133 CRC cases to determine the clinicopathological significance of FANCD2 expression.

RESULTS

The mean level of FANCD2 mRNA expression in tumor tissue specimens was significantly higher than in nontumor tissue. FANCD2 expression was found to be a significant factor affecting lymph node metastasis: the high FANCD2 expression group had a significantly poorer prognosis than the low expression group.

CONCLUSIONS

This study suggests that PCCA can be used to identify genes related to clinicopathological features. Furthermore, high FANCD2 expression was a significant independent factor for lymph node metastasis.

Methylation and expression of p14ARF in colorectal cancer

AIM: To investigate p14ARF (alternative reading frame) methylation and expression in colorectal cancer and to analyze their relationship with the biological behavior of colorectal cancer.

METHODS: The methylation-specific polymerase chain reaction (MSP) method was used to detect p14ARF gene methylation in 30 colorectal cancer specimens, 30 colorectal adenoma specimens, and 30 normal mucosa specimens. The expression of p14ARF mRNA and protein in these specimens was detected by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry, respectively.

RESULTS: The expression level of p14ARF mRNA in colorectal cancer was not only lower than that in colorectal adenoma (0.283 ± 0.011 vs 0.721 ± 0.023, P < 0.05) but also significantly lower than that in normal mucosa tissue (0.283 ± 0.011 vs0.958 ± 0.015, P < 0.01). Similar results were also obtained for the positive rate of p14ARF protein expression (20.0% vs56.7%, P < 0.05; and 20.0% vs 76.7%, P < 0.01). The methylation rates of the p14ARF gene were 46.6%, 20.0% and 0.0% in colorectal cancer, colorectal adenoma and normal mucosa tissue, respectively, with significant differences among the three groups. The methylation of p14ARF is correlated with cancer differentiation and lymph node metastasis (both P < 0.05).

CONCLUSION: The methylation of p14ARF may be involved in the evolution of colorectal cancer and may be an early event in the carcinogenesis of colorectal cancer. Therefore, p14ARF methylation may be used as a marker for early diagnosis of colorectal cancer.

Prevalence and risk of colorectal adenoma in asymptomatic Koreans aged 40-49 years undergoing screening colonoscopy

BACKGROUND AND AIM

Colorectal cancer screening is recommended for average-risk persons beginning at age 50. However, information about the incidence and risk factors of precursor adenoma in preceding decades is limited. The aim of this study was to determine the prevalence and risk factors of colorectal adenoma in persons aged 40-49 years and to compare the data with those aged 30-39 years and 50-59 years.

METHODS

A cross-sectional study of 5254 asymptomatic subjects who underwent screening colonoscopy was conducted. Data were stratified by age into three groups: 608 aged 30-39 years, 1930 aged 40-49 years, and 2716 aged 50-59 years.

RESULTS

Prevalence of overall adenomas was 10.4% in the 30-39 years age group, 22.2% in the 40-49 years age group, and 32.8% in the 50-59 years age group. Advanced adenoma was found in 0.7% of the 30-39 years age group, 2.7% of the 40-49 years age group, and 4.1% of the 50-59 years age group. In the 40-49 years age group, male sex and current smoking habits showed associations with low-risk adenoma after multiple adjustments. Moreover, male sex (odds ratio [OR] = 1.55, 95% confidence interval [CI]: 1.02-3.23), current smoking (OR = 1.58, 95%CI: 1.06-3.50), and family history of colorectal cancer (OR = 2.54, 95%CI: 1.16-5.56) were independent predictors of advanced adenoma in this age group.

CONCLUSIONS

Prevalence of adenoma in subjects aged 40-49 years was higher than in previous studies. Male sex and current smoking habits along with a family history of colorectal cancer were associated with advanced adenoma in this age group.

Relationship of non-alcoholic fatty liver disease to colorectal adenomatous polyps

BACKGROUND AND AIMS

Metabolic syndrome and insulin resistance are associated with a higher risk of colon cancer. Non-alcoholic fatty liver disease (NAFLD) is regarded as a manifestation of metabolic syndrome in the liver. This investigation was initiated to determine whether NAFLD has a relationship to colorectal adenomatous polyps.

METHODS

We examined the 2917 participants who underwent a routine colonoscopy at Kangbuk Samsung Hospital in 2007. We divided the 2917 subjects into the adenomatous polyp group (n = 556) and the normal group (n = 2361). Anthropometric measurements, biochemical tests for liver and metabolic function, and abdominal ultrasonographs were assessed.

RESULTS

The prevalence of NAFLD was 41.5% in the adenomatous polyp group and 30.2% in the control group. By multiple logistic regression analysis, NAFLD was found to be associated with an increased risk of colorectal adenomatous polyps (odds ratio, 1.28; 95% confidence interval, 1.03-1.60). An increased risk for NAFLD was more evident in patients with a greater number of adenomatous polyps.

CONCLUSION

NAFLD was associated with colorectal adenomatous polyps. Further studies are needed to confirm whether NAFLD is a predictor for the development of colorectal adenomatous polyps and cancer.

SFRP4 was overexpressed in colorectal carcinoma

PURPOSE

Secreted frizzled related proteins (SFRPs) play important roles in tumor progress through antagonizing Wnt signaling. However, SFRPs has not been systematically studied in colorectal tumors. The primary purpose of the study was to discuss the relationship between the expression of SFRPs and the clinicopathologic features of colorectal cancer (CRC).

METHODS

The mRNA expressions of SFRPs were analyzed in 20 paired CRC and adjacent non-cancerous tissues by quantitative real-time RT-PCR. The protein expression of SFRP1 and SFRP4 were verified by Western blot in those 20 paired samples and were further detected by immunohistochemistry (IHC) in other 206 colorectal tissues.

RESULTS

The mRNA levels of SFRP1 and SFRP5 were significantly downregulated in 85 and 80% of CRC, respectively; but SFRP4 was overexpressed in 16 of 20 CRC samples. These findings were concordant with those obtained from the Western blotting in SFRP1 and SFRP4. Moreover, IHC analysis demonstrated increasing SFRP4 expression and decreasing SRFP1 levels in CRC compared with HIN and adenoma.

CONCLUSIONS

SFRP1 and SFRP4 appear to be candidate markers for colorectal lesions. Unlike SFRP1 as a negative regulator for CRC carcinogenesis, SFRP4 may play quite different biological role in CRC.

Association of selected polymorphisms of CCND1, p21, and caspase8 with colorectal cancer risk

It has been well elucidated that the signal transduction of cell-cycle control pathway and apoptosis pathway plays an important role in the normal growth and differentiation of organisms. To test the hypothesis that mutants of key genes involved in cell-cycle regulation and apoptosis might contribute to the increased risk of colorectal cancer (CRC), a population-based case-control study was carried out in Jiashan County, Zhejiang Province. The study population was composed of 373 CRC cases and 838 controls. Five genetic variants including CCND1 G870A, p21 codon31 C/A, p21 3'UTR C/T, caspase8 IVS12-19G/A, and caspase8 6n del/ins were genotyped. The associations of the polymorphisms with CRC were estimated by logistical regression model after adjustment for the important covariates. The interactive effect among the five selected genetic polymorphisms on CRC was explored by multifactor dimensionality reduction (MDR) software. The significant association between five single-nucleotide polymorphisms (SNPs) and CRC risk was not observed, respectively. However, caspase8 del/del showed a marginally significant association with the increased risk of rectum cancer [adjusted odds ratio (OR) (95% confidence interval, CI) = 1.92 (0.97-3.79); P = 0.06]. Furthermore, the MDR analysis indicated that the best interactive model for CRC included three factors-CCND1 G870A, caspase8 IVS12-19G/A, and caspase8 6 n del/ins-with 53.44% testing balanced accuracy and 10/10 cross-validation consistency, but the model was no longer significant after the 1000 times permutation test (P = 0.25). Our findings suggest that the selected polymorphisms of p21, CCND1, and caspase8 may not contribute to the risk of colorectal cancer.

Serum metabolite profiling of human colorectal cancer using GC-TOFMS and UPLC-QTOFMS

Colorectal carcinogenesis involves the overexpression of many immediate-early response genes associated with growth and inflammation, which significantly alters downstream protein synthesis and small-molecule metabolite production. We have performed a serum metabolic analysis to test the hypothesis that the distinct metabolite profiles of malignant tumors are reflected in biofluids. In this study, we have analyzed the serum metabolites from 64 colorectal cancer (CRC) patients and 65 healthy controls using gas chromatography time-of-flight mass spectrometry (GC-TOFMS) and Acquity ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry (Acquity UPLC-QTOFMS). Orthogonal partial least-squares discriminate analysis (OPLS-DA) models generated from GC-TOFMS and UPLC-QTOFMS metabolic profile data showed robust discrimination from CRC patients and healthy controls. A total of 33 differential metabolites were identified using these two analytical platforms, five of which were detected in both instruments. These metabolites potentially reveal perturbation of glycolysis, arginine and proline metabolism, fatty acid metabolism and oleamide metabolism, associated with CRC morbidity. These results suggest that serum metabolic profiling has great potential in detecting CRC and helping to understand its underlying mechanisms.

Colorectal carcinoma: Importance of colonic environment for anti-cancer response and systemic immunity

The intestinal environment is considered to play an important role both in colorectal tumor development and in the evolution and modulation of mucosal immunity. Studies in animals reared in germ-free (GF, without any intestinal microflora) versus conventional (CV, with regular microflora in bowel) conditions can aid in clarifying the influence of bacteria on carcinogenesis and anti-cancer immune responses in situ. The lower incidence of colon cancers and better immunological parameters in GF animals versus CV ones after chemically-induced carcinogenesis raises questions about specific characteristics of the immunological networks in each respective condition. Different levels of tolerance/regulatory mechanisms in the GF versus CV animals may influence the development of immune responses not only at the level of mucosal, but also at the systemic, immunity. We hypothesize that GF animals can better recognize and respond to evolving neoplasias in the bowel as a consequence of their less-tolerogenic immunity (i.e., due to their more limited exposure to antigens to become tolerated against at the intestinal level). In this paper, we review the role of bacteria in modulating gut environment and mucosal immunity, their importance in cancer development, and aspects of immune regulation (both at local and systemic level) that can be modified by bacterial microflora. Lastly, the use of GF animals in comparison with conventionally-raised animals is proposed as a suitable and potent model for understanding the inflammatory network and its effect on cancer immunity especially during colorectal cancer development.

Geoditin A induces oxidative stress and apoptosis on human colon HT29 cells

Geoditin A, an isomalabaricane triterpene isolated from the marine sponge Geodia japonica, has been demonstrated to dissipate mitochondrial membrane potential, activate caspase 3, decrease cytoplasmic proliferating cell nuclear antigen (PCNA), and induce apoptosis of leukemia cells, but the underlying mechanism remains unclear [1]. In this study, we found fragmentation of Golgi structure, suppression of transferrin receptor expression, production of oxidants, and DNA fragmentation in human colon cancer HT29 cells after treatment with geoditin A for 24 h. This apoptosis was not abrogated by chelation of intracellular iron with salicylaldehyde isonicotinoyl hydrazone (SIH), but suppressed by N-acetylcysteine (NAC), a thiol antioxidant and GSH precursor, indicating that the cytotoxic effect of geoditin A is likely mediated by a NAC-inhibitable oxidative stress. Our results provide a better understanding of the apoptotic properties and chemotherapeutical potential of this marine triterpene.

Overexpression of neutrophil gelatinase-associated lipocalin and its receptor in colorectal carcinoma: Significant correlation with cell differentiation and tumour invasion

Neutrophil gelatinase-associated lipocalin (NGAL), a member of the lipocalin family, is related to imflammation and tumour. Recently, a specific cell-surface receptor (24p3R/NGALR) for lipocalin 24p3 was reported. However, the characteristics of NGALR expression in colorectal carcinoma (CRC) are not known. The objectives of this study were to investigate the expression of NGAL and NGALR in CRC specimens, and determine any relationship between the expression of these proteins and tumour progression. In the present study, CRC specimens of 102 patients were obtained, and the expression of NGAL, NGALR, ferritin and Ki67 was analyzed in paraffin sections by immunohistochemistry. Statistical analyses of the data collected were performed with SPSS software. We found that the cytoplasmic staining of NGAL, NGALR and ferritin, as well as the nuclear staining of Ki67 were significantly up-regulated in CRC tissues compared with normal colorectal tissues. Expression of NGAL was related to the deeper invasion of CRC (P=0.026), while NGALR was significantly associated with a deeper invasion (P=0.018) and a high degree of Tumor, Node and Metastasis stages (P=0.042) in CRC. The NGAL/NGALR co-expression was associated with poor cellular differentiation (P=0.004). Positive correlations between NGAL and NGALR (r=0.432, P<0.01), NGAL and ferritin (r=0.374, P<0.001), NGALR and Ki67 (r=0.228, P<0.05), NGAL/NGALR co-expression and ferritin (r=0.349, P<0.001), as well as NGAL/NGALR co-expression and Ki67 (r=0.205, P<0.05) were observed. However, the expression of NGAL or NGALR was not significantly associated with patient survival. These findings detected an elevated expression of NGAL and NGALR resulting in poor cellular differentiation and a deeper invasion of CRC. Thus, NGALR may be a novel target for the treatment of CRC.

Trends of Gastrointestinal Diseases at a Single Institution in Korea over the Past Two Decades

Background/Aims

The lifestyle changes that have accompanied economic growth have influenced disease patterns in Korea. Changing patterns of gastrointestinal (GI) diseases over the past two decades were investigated in the present study.

Methods

Data from inpatients with specific GI diseases, as defined by the International Classification of Diseases code, were extracted from the database at a tertiary medical facility for 1990, 1996, and 2006.

Results

Admission rates for GI diseases increased between 1990 and 2006. The most prevalent disease in 1990 was gastric cancer, followed by appendicitis and colorectal cancer. However, by 2006, gastric cancer, colon cancer, and colon adenoma or polyps had become the most prevalent diseases. Although gastric cancer showed a decreasing trend, the rate of colon cancer doubled over two decades. Furthermore, rates of detection and endoscopic treatment of early gastric cancer and adenoma of the stomach and colon have increased noticeably. Newly emerging diseases include inflammatory bowel disease and gastroesophageal reflux. There was no change in the incidence of peptic ulcer, but ulcer-related complications and the numbers treated surgically decreased.

Conclusions

The findings of this study indicate that the clinical trends of GI diseases in Korea have changed in a similar way to those in the West. Early detection of a GI neoplasm will continue to increase with the establishment of cancer-screening programs, resulting in a rising need for minimally invasive treatments.

TGFB1 509 C/T polymorphism and colorectal cancer risk: a meta-analysis

Transforming growth factor β (TGF-β) is a cytokine. The TGF-β signaling pathway plays an important role in controlling cell proliferation and differentiation involved in colorectal carcinogenesis. In mammalian cells, TGFB1 is the most abundant subtype of TGF-β. The 509 C/T polymorphism in TGFB1 has been implicated in colorectal cancer risk. However, published data remain conflicting. To derive a more precise estimation of the relationship, a meta-analysis of 994 cases and 2,335 controls from five published case-control studies was performed. Overall, significantly increased colorectal cancer risks were found for CC versus TT (OR=1.62; 95% CI: 1.30-2.02; Pheterogeneity=0.118), TC+CC versus TT (OR=1.30; 95% CI: 1.08-1.58; Pheterogeneity=0.259) and CC versus TC+TT (OR=1.48; 95% CI: 1.26-1.75; Pheterogeneity=0.244). In the subgroup analysis by ethnicity, significantly increased risks were also found among Asians for CC versus TT (OR=1.77; 95% CI: 1.40-2.24; Pheterogeneity=0.519), TC+CC versus TT (OR=1.38; 95% CI: 1.13-1.68; Pheterogeneity=0.679) and CC versus TC+TT (OR=1.58; 95% CI: 1.31-1.89; Pheterogeneity=0.340). However, no significant associations were found among Europeans for all genetic models. This meta-analysis showed that TGFB1 509 C allele is a risk factor for developing colorectal cancer in Asians.

A prospective evaluation of the feasibility of primary screening with unsedated colonoscopy

BACKGROUND

Colonoscopy is the most effective screening tool for colorectal cancer. In Taiwan, colonoscopy is used much less than sigmoidoscopy for screening because sedation significantly increases the cost and is not readily available, and unsedated colonoscopy is considered to be poorly tolerated. However, unsedated colonoscopy has been shown to be well accepted and may improve the cost-effectiveness and access to colonoscopic screening.

OBJECTIVES

To compare the feasibility of unsedated colonoscopy and sigmoidoscopy for primary screening and to analyze factors associated with acceptance of the procedures and need for sedation.

DESIGN

Single center, prospective.

SETTING

National Taiwan University Medical Center. POPULATION AND INTERVENTIONS: A consecutive series of 261 subjects without history of colonoscopy or sigmoidoscopy who underwent unsedated colonoscopy (n = 176) or sigmoidoscopy (n = 85) for primary screening.

MAIN OUTCOME MEASUREMENTS

Pain scores, acceptance, and need for sedation.

RESULTS

No significant differences in pain, acceptance, and need for sedation were found between the colonoscopy and sigmoidoscopy groups. Only 9.6% in the colonoscopy group and 10.1% in the sigmoidoscopy group considered sedation necessary. Multivariate analyses revealed that the examinee's sex and the endoscopist, but not the type of endoscopic examination, were associated with the severity of pain and need for sedation.

LIMITATIONS

Nonrandomized study design.

CONCLUSIONS

Unsedated colonoscopy for primary screening is well accepted in nine tenths of examinees who accept this option and is similar to sigmoidoscopy in pain, acceptance, and need for sedation. Primary screening with unsedated colonoscopy is feasible, as with sigmoidoscopy.

A platinum agent resistance gene, POLB, is a prognostic indicator in colorectal cancer

BACKGROUND

Recent progress in chemotherapy with platinum agents has improved clinical outcome in colorectal cancer (CRC), but there are no useful markers to predict the efficacy of such agents. DNA polymerase beta (POLB) mediates the efficacy of chemotherapy through DNA repair machinery. We analyzed the significance of POLB expression in CRC chemotherapy and its potential as a prognostic indicator.

METHODS

Using microarray, POLB was found to be overexpressed in CRC cells compared with corresponding normal colon epithelial cells. We determined the susceptibility of POLB-suppressed cells to cisplatin and oxaliplatin. We evaluated POLB mRNA expression in 97 CRC cases to determine the clinicopathologic significance of POLB expression.

RESULTS

We found the suppression of POLB altered the in vitro susceptibility to cisplatin but not to oxaliplatin. In 97 CRC cases, lymph node metastasis, distant metastasis and TNM classification were significantly greater in the high POLB group than in the low group (P < 0.05). Patients with high POLB expression had significantly poorer prognosis than those with low expression (P < 0.05).

CONCLUSIONS

The data indicate POLB is overexpressed in CRC cases with high malignant potential. We suggest POLB could be useful as a predictive marker for selection of patients responsive to cisplatin.

International trends in colorectal cancer incidence rates

BACKGROUND

Previous studies have documented significant variations in colorectal cancer incidence rates and trends regionally and across countries. However, no study has examined the worldwide pattern using the most recently updated incidence data from the IARC.

METHODS

We obtained sex-specific colorectal cancer incidence for 1953-57 through 1998-2002 by cancer registry from Cancer Incidence in Five Continents (CI5) databases. For 51 cancer registries with long-term incidence data, we assessed the change in the incidence rates over the past 20 years by calculating the ratio of the incidence rates in 1998-2002 to that in 1983-87.

RESULTS

Colorectal cancer incidence rates for both males and females statistically significantly increased from 1983-87 to 1998-2002 for 27 of 51 cancer registries considered in the analysis, largely confined to economically transitioning countries including Eastern European countries, most parts of Asia, and select countries of South America. These increases were more prominent for men than for women. We also observed substantial variations in colorectal cancer incidence trends within countries such as Japan. Similarly, trends in Israel and Singapore varied significantly according to ethnicity. The United States is the only country where colorectal cancer incidence rates declined in both males and females.

CONCLUSIONS

Colorectal cancer incidence rates continue to increase in economically transitioning countries, with incidence rates among men in the Czech Republic and Slovakia exceeding the peak incidence observed in the United States and other long-standing developed nations. Targeted prevention and early detection programs could help reverse the trend in these countries.

Ursolic acid inhibits proliferation and induces apoptosis of HT-29 colon cancer cells by inhibiting the EGFR/MAPK pathway

OBJECTIVE

To investigate the effects of ursolic acid on the proliferation and apoptosis of human HT-29 colon cancer cells.

METHODS

3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry assays were performed to evaluate the effects of ursolic acid on the growth and apoptosis of HT-29 cells. Western blot analysis was applied to investigate the inhibitory effects of ursolic acid on the phosphorylation of the epidermal growth factor receptor (EGFR), extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (p38 MAPK), and the activity of B cell leukemia-2 (Bcl-2), B cell leukemia-xL (Bcl-xL), caspase-3, and caspase-9.

RESULTS

Ursolic acid inhibited the growth of HT-29 cells in dose- and time-dependent manners. The median inhibition concentration (IC50) values for 24, 48, and 72 h treatment were 26, 20, and 18 micromol/L, respectively. The apoptotic rates of 10, 20, and 40 micromol/L ursolic acid treatments for 24 h were 5.74%, 14.49%, and 33.05%, and for 48 h were 9%, 21.39%, and 40.49%, respectively. Ursolic acid suppressed the phosphorylation of EGFR, ERK1/2, p38 MAPK, and JNK, which is well correlated with its growth inhibitory effect. 10, 20, and 40 micromol/L ursolic acid significantly inhibited the proliferation of EGF-stimulated HT-29 cells (P<0.05). Cell proliferation was most significantly inhibited when treated with 10 and 20 micromol/L ursolic acid combined with 200 nmol/L AG 1478 or 10 micromol/L U0126 (P<0.01). Besides, it also down-regulated the expression of Bcl-2 and Bcl-xL and activated caspase-3 and caspase-9.

CONCLUSION

Ursolic acid induces apoptosis in HT-29 cells by suppressing the EGFR/MAPK pathway, suggesting that it may be a potent agent for the treatment of colorectal cancer.

Factors associated with practice of colorectal cancer screening among primary care physicians in a Chinese population: a cross-sectional study

OBJECTIVES

Primary care physicians (PCPs) are influential in colorectal cancer (CRC) screening uptake in the community. This study aims to evaluate the factors associated with PCPs' practice of CRC screening among asymptomatic patients in a Chinese population.

METHODS

A validated postal questionnaire was sent to all practicing PCPs who were members of a community-based network in Hong Kong. Three separate rounds of reminder letters were sent to non-respondents. Binary logistic regression analysis was used with ever-referral for CRC screening in the past 12 months as the outcome variable. Predictor variables include physicians' gender, clinical experience, types of practice, and attitudes towards CRC screening.

RESULTS

Of 428 eligible physicians, 263 (61.4%) responded. A total of 187 physicians (71.1%) had referred patients for CRC screening in the past 1 year. Among all asymptomatic patients aged 50 years or older, physicians reported referring only 3.0% (1.0-10.0%) [median (interquartile range)] of patients. Colonoscopy (57.0%) and fecal occult blood testing (FOBT) (46.4%) were the most commonly recommended tests for these asymptomatic patients. Family history of CRC (58.6%) and patients' concern about CRC (50.2%) were major reasons for referral. PCPs in private practice (adjusted odds ratio [aOR] 2.60, 95% C.I. 1.21-5.59) and those with positive attitude towards CRC screening (aOR 2.27, 95% C.I. 1.15-4.48) were more likely to recommend CRC screening.

CONCLUSIONS

PCPs' attitude towards CRC screening is a significant determinant of its practice. Future studies should identify and strengthen the influencers of PCPs' attitude to enhance CRC screening rates.

Modulated T-complex protein 1 ζ and peptidyl-prolyl cis-trans isomerase B are two novel indicators for evaluating lymph node metastasis in colorectal cancer: Evidence from proteomics and bioinformatics

Lymph node metastasis (LNM) is an important indicator for systematic therapy, which could increase the survival of colorectal cancer (CRC) patients. However, effective clinical evaluation for LNM is still absent to date. In this study, protein expression profiles of CRC tissues were compared between patients with and without LNM. Based on average expression level, 12 proteins were found to be differentially expressed in the CRC tissues with LNM, whose discrimination reliability was confirmed by PCA. With stepwise linear discriminant analysis, T-complex protein 1 ζ subunit and peptidyl-prolyl cis-trans isomerase B (PPIB) were identified as two main contributors for separating CRC tissues with positive LNM from those negative ones in both original-grouped and cross-validated-grouped cases, which was also supported in subsequent linear support vector machine analysis. In addition, the expression alterations of the two proteins were verified by Western blot and immunohistochemistry. Functional studies also confirmed the role of PPIB in migration and invasion of cancer cells. Taken together, the down-regulated T-complex protein 1 ζ subunit and up-regulated PPIB were identified as two promising indicators for the clinical evaluation of LNM in CRC patients.

Repeat-screening colonoscopy 5 years after normal baseline-screening colonoscopy in average-risk Chinese: a prospective study

OBJECTIVES

Although colonoscopy is considered the most accurate screening tool for colorectal neoplasm, the optimal interval of repeating a screening colonoscopy, particularly in average-risk subjects after a negative colonoscopy, is poorly defined. We determine the 5-year risk of advanced neoplasia on rescreening colonoscopy in a cohort of average-risk Chinese subjects.

METHODS

We invited a cohort of asymptomatic average-risk Chinese subjects (aged 55-75 years) who were recruited in our previous screening colonoscopy studies to undergo a repeat colonoscopy at the end of 5 years. The rates of advanced colorectal neoplasia at the end of 5 years in these subjects were determined according to their baseline colonoscopy findings.

RESULTS

A total of 511 of the 620 eligible subjects underwent repeat-screening colonoscopy at the end of 5 years. Among them, 401 subjects had no baseline neoplasia (370 with no baseline polyps and 31 with hyperplastic polyps). In subjects with no baseline polyp, 24.6% were found to have at least one adenoma and 1.4% had advanced neoplasia on rescreening. The number needed to rescreen for one advanced neoplasia in subjects with no baseline polyp was 74 (95% confidence interval (CI), 32-168). The prevalence of advanced neoplasia at 5 years in subjects with baseline-advanced neoplasia was 20.7% (relative risk 19.6; 95% CI, 5.2-74.1; vs. subjects with no baseline polyp). The presence of baseline-advanced neoplasia (odds ratio (OR) 13.1; 95% CI, 4.1-41.7) and age in years (OR 1.11; 95% CI, 1.01-1.22) are two independent factors for development of advanced neoplasia at 5 years.

CONCLUSIONS

The risk of advanced neoplasia is sufficiently low 5 years after a normal screening colonoscopy in Chinese subjects.

Identification of S100A8 and S100A9 as serological markers for colorectal cancer

In search of novel serological protein biomarkers for human colorectal cancer (CRC), we analyzed CRC tissues using two-dimensional difference in-gel electrophoresis (2D-DIGE) on a narrow range IPG strip (pH 5.5-6.7). By comparing tumor tissues with matched normal tissues in a pairwise manner (n = 6), we identified 34 up-regulated and 17 down-regulated spots with intensity changes greater than 2-fold (Student's t-test, p < 0.05). Expression of both mRNA and protein levels of four proteins, adenosylhomocysteinase, Nm23-H1, S100A8 and S100A9, in CRC tissues was further evaluated by semiquantitative RT-PCR and Western blot analysis. The results revealed that all four proteins were elevated in the tumor tissues. We also confirmed, by immunohistochemistry, that adenosylhomocysteinase and Nm23-H1 were overexpressed in tumor cell cytoplasm and that S100A8 and S100A9 proteins were strongly expressed in tumor infiltrating immune cells. Western blot analysis with fractionated plasma samples showed that S100A8 and S100A9 were significantly increased in the plasma of CRC patients (n = 77) and colorectal adenoma patients (n = 11), compared to healthy controls (n = 21). The area under a receiver operating characteristic (ROC) curve was 0.91 for S100A8 and 0.89 for S100A9, which was superior to the established tumor marker carcinoembryonic antigen with 0.78 for the area under the ROC curve. Some patients with inflammatory diseases such as pancreatitis also showed elevated levels of the proteins. Importantly, in comparison to the control group, both proteins showed a remarkable change at the early stage of cancer. Therefore, we suggest S100A8 and S100A9 as candidates for serological biomarkers in combination with other serum markers that aid CRC diagnosis.

Surgical outcome of abdominoperineal resection for low rectal cancer in a Nigerian tertiary institution

BACKGROUND

Rectal cancer is a lifestyle-related illness with an increasing incidence in all developing countries in the last decade. Abdominoperineal resection (APR) offers a good oncologic clearance for low rectal cancer. The remaining controversies surrounding APR, as it is performed in a tertiary center in Nigeria, involve defining the role the operation plays in the management of existing rectal problems and determining what outcomes can be expected. The present study was aimed at examining the surgical outcomes of APR for low rectal cancers in a Nigerian tertiary institution.

MATERIALS AND METHODS

This single-institution, retrospective, descriptive study analyzed APR rate, patient sex and age, subsite involvement, the diagnostic process, follow-up, and survival patterns after treatment of low rectal cancers. The study was conducted at Obafemi Awolowo University Teaching Hospital Complex Ile-Ife, Nigeria, between January 1989 and December 2007.

RESULTS

During the 18-year period, 36 patients underwent APR. This accounts for 24.0% of all patients that had low rectal cancer. The age of the patients ranged from 29 years to 74 years (median: 58.9 years). Most of the patients were 60 years of age or older, and the majority were women (55.9%). The median duration of symptoms was 12 months, and all patients sought medical care for bleeding per rectum. Close to 80% of patients had advanced disease at presentation. Postoperatively, 17 patients (50%) had at least one complication and one patient (2.9%) died. Four (11.8%) patients had recurrence of the tumor, and in every case, recurrence occurred within the first year after operation. Operative blood loss (p = 0.006), degree of differentiation of the tumor (p = 0.011), distance from the anal verge (p = 0.033), and operative stage (p = 0.005) were found to significantly affect the outcome of treatment for the patients who underwent APR. The operative stage similarly affected the survival of patients (Mantel Cox = 0.026).

CONCLUSIONS

Despite the advanced disease of our patients, the outcome of management appears to be comparable with results reported from other centers.

Prevalence and characteristics of nonpolypoid colorectal neoplasm in an asymptomatic and average-risk Chinese population

BACKGROUND AND AIMS

Evidence from Japanese studies suggests that nonpolypoid colorectal neoplasia (NP-CRN) tends to be more pathologically advanced than polypoid neoplasia. However, data are limited regarding the prevalence of NP-CRN in an average-risk population. In addition, the diagnostic yield of the fecal occult blood test (FOBT) in relation to different types of colorectal neoplasms remains unclear. We prospectively investigated the prevalence and characteristics of polypoid and nonpolypoid colorectal lesions in an asymptomatic and average-risk Chinese population.

METHODS

The study included 12,731 asymptomatic Chinese subjects (8372 of whom were average-risk subjects) who underwent screening colonoscopy. The prevalence, histopathologic findings, and topographic distribution of polypoid and nonpolypoid colorectal lesions were determined and analyzed. The diagnostic yield of FOBT, in relation to lesion morphology, also was assessed.

RESULTS

NP-CRN was detected in 552 (4.3%) asymptomatic and 348 (4.2%) average-risk subjects. The prevalence of depressed NP-CRN was 0.18% in both asymptomatic and average-risk subjects. A higher proportion of smaller-sized but high-grade dysplasia and invasive carcinoma beyond the submucosal layer was noted for depressed NP-CRN compared with flat NP-CRN or polypoid neoplasia. The diagnostic yield of FOBT was comparable in depressed lesions and their polypoid counterparts.

CONCLUSIONS

The prevalence of NP-CRN is substantial in both asymptomatic and average-risk Chinese individuals. Some subcategories of NP-CRN in this population tend to have more advanced pathologic characteristics. These findings may lead to modification of screening and prevention strategies for colorectal cancer.