Diagnostic value of stool DNA testing for multiple markers of colorectal cancer and advanced adenoma: a meta-analysis.

BACKGROUND AND OBJECTIVES: The diagnostic value of stool DNA (sDNA) testing for colorectal neoplasms remains controversial. To compensate for the lack of large-scale unbiased population studies, a meta-analysis was performed to evaluate the diagnostic value of sDNA testing for multiple markers of colorectal cancer (CRC) and advanced adenoma. METHODS: The PubMed, Science Direct, Biosis Review, Cochrane Library and Embase databases were systematically searched in January 2012 without time restriction. Meta-analysis was performed using a random-effects model using sensitivity, specificity, diagnostic OR (DOR), summary ROC curves, area under the curve (AUC), and 95% CIs as effect measures. Heterogeneity was measured using the χ(2) test and Q statistic; subgroup analysis was also conducted. RESULTS: A total of 20 studies comprising 5876 individuals were eligible. There was no heterogeneity for CRC, but adenoma and advanced adenoma harboured considerable heterogeneity influenced by risk classification and various detection markers. Stratification analysis according to risk classification showed that multiple markers had a high DOR for the high-risk subgroups of both CRC (sensitivity 0.759 [95% CI 0.711 to 0.804]; specificity 0.883 [95% CI 0.846 to 0.913]; AUC 0.906) and advanced adenoma (sensitivity 0.683 [95% CI 0.584 to 0.771]; specificity 0.918 [95% CI 0.866 to 0.954]; AUC 0.946) but not for the average-risk subgroups of either. In the methylation subgroup, sDNA testing had significantly higher DOR for CRC (sensitivity 0.753 [95% CI 0.685 to 0.812]; specificity 0.913 [95% CI 0.860 to 0.950]; AUC 0.918) and advanced adenoma (sensitivity 0.623 [95% CI 0.527 to 0.712]; specificity 0.926 [95% CI 0.882 to 0.958]; AUC 0.910) compared with the mutation subgroup. There was no significant heterogeneity among studies for subgroup analysis. CONCLUSION: sDNA testing for multiple markers had strong diagnostic significance for CRC and advanced adenoma in high-risk subjects. Methylation makers had more diagnostic value than mutation markers.

High-resolution melting assay (HRMA) is a simple and sensitive stool-based DNA Test for the detection of mutations in colorectal neoplasms.

BACKGROUND: Stool-based DNA testing for colorectal cancer is becoming a favored alternative to existing DNA screening tests. However, current methods of analysis often become more complicated and costly with increased sensitivity. The high-resolution melting assay (HRMA) is a simple and rapid mutation scanning method with low cost and superb accuracy. In this study, we verified the accuracy of HRMA for screening KRAS/TP53 mutations in stool-isolated DNA from patients with colorectal cancer. MATERIALS AND METHODS: Comparing to direct DNA sequencing, the accuracy of HRMA was verified by detecting KRAS/TP53 mutations in 2 independent stages. In study stage I, both tissue and stool samples from colorectal neoplasm patients were analyzed. In study stage II, stool samples from patients with colorectal neoplasms, and normal controls in clinical screening settings were examined. RESULTS: In study stage I, the HRMA identified 14 of 17 target mutations (82.4%) in stools from cancer patients, and 4 of 5 (80.0%) target mutations in stools from advanced adenoma patients. The mutation detection rate in fecal samples (45.0%; 18/40) and referred tissue samples (55.0%; 22/40) was highly consistent (κ = 0.79). The HRMA detected 1% mutant DNA in a background of wild type DNA. In study stage II, the HRMA assay detected 58.8% (20/34) mutations in tumor samples, 41.5% (17/41) in advanced adenomas samples, and 3.33% (2/60) in age-matched normal control samples. The results from HRMA and DNA sequencing revealed 100% sensitivity and specificity in both tissue and stool samples. CONCLUSION: HRMA is a simple, reliable, and sensitive method for detecting DNA mutations in the stool samples from patients with colorectal neoplasms.

Is high resolution melting analysis (HRMA) accurate for detection of human disease-associated mutations? A meta analysis.

BACKGROUND: High Resolution Melting Analysis (HRMA) is becoming the preferred method for mutation detection. However, its accuracy in the individual clinical diagnostic setting is variable. To assess the diagnostic accuracy of HRMA for human mutations in comparison to DNA sequencing in different routine clinical settings, we have conducted a meta-analysis of published reports. METHODOLOGY/PRINCIPAL FINDINGS: Out of 195 publications obtained from the initial search criteria, thirty-four studies assessing the accuracy of HRMA were included in the meta-analysis. We found that HRMA was a highly sensitive test for detecting disease-associated mutations in humans. Overall, the summary sensitivity was 97.5% (95% confidence interval (CI): 96.8-98.5; I(2) = 27.0%). Subgroup analysis showed even higher sensitivity for non-HR-1 instruments (sensitivity 98.7% (95%CI: 97.7-99.3; I(2) = 0.0%)) and an eligible sample size subgroup (sensitivity 99.3% (95%CI: 98.1-99.8; I(2) = 0.0%)). HRMA specificity showed considerable heterogeneity between studies. Sensitivity of the techniques was influenced by sample size and instrument type but by not sample source or dye type. CONCLUSIONS/SIGNIFICANCE: These findings show that HRMA is a highly sensitive, simple and low-cost test to detect human disease-associated mutations, especially for samples with mutations of low incidence. The burden on DNA sequencing could be significantly reduced by the implementation of HRMA, but it should be recognized that its sensitivity varies according to the number of samples with/without mutations, and positive results require DNA sequencing for confirmation.

[Screening of high-risk group with colorectal cancer].

OBJECTIVE: To measure the rate of high-risk group and the detection rate of colorectal cancer (CRC) in communities in Guangdong province and to provide scientific rationales for formulating mass screening plans in high-risk group. METHODS: Mass survey was conducted by questionnaire combined fecal occult blood test (FOBT) in Huizhou region, Guangdong Province, to sort out the high-risk population of CRC. Then the high-risk population was screened by colonoscopy and pathology to identify CRC. The differences were compared by direct expenditure which was used to calculate screening cost. RESULTS: A total of 68,953 people were surveyed. There were 940 people in high-risk group (detection rate: 1.36%), 3118 in immunity FOBT positive group (detection rate: 4.52%), Merging aforementioned two groups, there were 3870 in population at risk (detection rate: 5.61%). The CRC detection rate in high-risk group, immunity FOBT positive group, population at risk and average-risk group was 506.3/10(5), 314.3/10(5), 315.9/10(5) and 17.7/10(5) respectively. The positive predictive value of CRC screening scheme by high-risk group questionnaire-colonoscopy was 0.43% while CRC screening scheme by FOBT-colonoscopy 0.22%. In terms of direct expenditure of CRC per case in high-risk group and immunity FOBT positive group was 47,834.5 yuan and 82,303.6 yuan. The latter was 1.7 times than that of the former. CONCLUSIONS: The scheme of questionnaire combined FOBT for CRC is an effective way in mass survey. The scheme by high-risk group questionnaire-colonoscopy has a much better cost-effectiveness than that of the scheme by FOBT-colonoscopy so that it should be one of the preferred methods for individual screening in high-risk group.

Colorectal cancer in Guangdong Province of China: a demographic and anatomic survey.

AIM: To determine the basic demographic features of colorectal cancer (CRC) in five hospitals located in four different areas of Guangdong Province, China. METHODS: A review of patient records from 1986 to 2006 from five hospitals was conducted. Patient data was obtained, including age, gender, location of lesions, staging and histological type of CRC. The Chi-square test was used to assess differences in rates and a significance level of 0.05 was used. Univariate comparisons were made via Fisher's exact tests. RESULTS: Analysis was carried out on 8172 CRC patents, 6.1% (499/8172) of the patients were aged < or = 30 years. The peak incidence was between the ages 61-70 years (27.8%). The mean age at CRC diagnosis increased from 52 years (1986-1988) to 60 years (2004-2006) and the proportion of young CRC patients decreased from 8.0% to 5.9% over the same period. Of 8172 lesions, 4434 (54.3%) were located in rectum and 3738 (45.7%) in colon. The incidence of rectal cancer decreased significantly from 59.4% (1989-1991) to 51.8% (2004-2006) and right sided colon cancer increased from 40.6% to 48.2%. The mean age, anatomic distribution, histological type and differentiation degree were significantly different among the four geographical areas (P < 0.05). CONCLUSION: The hospitalization rate for CRC has increased in Guangdong in recent years. The characteristics of CRC from the five hospitals located in the four different areas of Guangdong Province are also different. Further studies are needed to assess more recent trend in the incidence and prevalence of CRC as well as the respective roles of genetic and environmental factors in CRC.

[Epidemiology investigation of colorectal cancer on community group in Guangdong province].

OBJECTIVE: To explore the epidemiology characteristics of colorectal cancer on community group in Guangdong province. METHODS: Huidong was took as the research spot to investigate the sickness and incidence of colorectal cancer among a whole community group in Guangdong province, and two projects were used simultaneously: "screening of colorectal cancer in high risk group" and "screening project using fecal occult blood test". The numeration time for population of 10 towns was set at July 1, 2005. Five towns were sampled out from Huidong with 100,859 persons. Meanwhile, the diseases and death cause registering system was established. RESULTS: The incidence of colorectal cancer in Huidong community group was 15.2/100,000 (male 17.2/100,000, female 13.0/100,000), the age-adjusted incidence was 17.6/100,000 (male 19.5/100,000, female 16.7/100,000). The morbidity was 41.9/100,000 (male 46.5/100,000, female 37.2/100,000), the age-adjusted morbidity was 49.0/100,000 (male 54.1/100,000, female 45.6/100,000). The mortality was 5.0/100,000 (male 5.9/100,000, female 4.0/100,000) and the age-adjusted morbidity was 6.4/100,000 (male 7.2/100,000, female 5.7/100,000). CONCLUSION: The incidence of colorectal cancer in Huidong community group is lower than that of high incidence area in China, but gets close to the normal incidence area of China and general level of the world.

[Effect of Tiam1 overexpression on proliferation and metastatic potential of human colorectal cancer].

OBJECTIVE: To confirm the role of Tiam1 (T lymphoma invasion and metastasis 1) gene in the proliferation and metastasis of colorectal cancer. METHODS: Proliferative and metastatic abilities of Tiam1 transfectant were investigated by subcutaneous injection of cells and surgical orthotopic transplantation (SOI) in mice. RESULTS: The expression of Tiam1 led to a pronounced increase in HT29/Tiam1 cell growth starting from day 7, up to 2.5 fold increase of tumor volume at day 20 post injection. Tumors in the HT29/Tiam1 group receiving surgical orthotopic implantation were significantly heavier than those in HT29/mock group (t = -14.916, P < 0.01). In vivo metastasis assay by SOI showed that in HT29/Tiam1 group, 7/7 of mice developed peritoneal metastases and 4/7 had hepatic lesions. In addition, one of the seven HT29/Tiam1 group mice had tumors in lung, spleen and lymph nodes. In the HT29/mock group, only 2/7 of animals had peritoneal metastases and none produced detectable tumor in the liver. CONCLUSIONS: Tiam1 gene plays an important role in the proliferation, invasion and metastasis of colorectal cancer. It may serve as a useful clinical marker for tumor progression and metastasis of colorectal cancer.

[The trend of clinical characteristics of colorectal cancer during the past 20 years in Guangdong province].

OBJECTIVE: To study the trend of clinical characteristics of colorectal cancer during the past 20 years in Gaungdong province. METHODS: The clinical data of 3870 cases of colorectal cancers confirmed pathologically who were hospitalized to Nanfang Hospital and Huizhou Municipal Hospital, Guangdong province, 1985 - 2004 were divided into 5-year groups and analyzed. RESULTS: The hospitalization number of colorectal cancer in the 2000 - 20004 5-year period was 102%, higher than that of the 1985 - 1989 period with an annual increase of 5.1%. The median age of incidence 2000 - 2004 was 58.6 years, 8.4 years higher than that in 1985 - 1989. The male to female ratio of the 3870 patients was 1.42:1. The male to female ratio 2000 - 2004 was 1.35:1, lower than that 1985 - 1989 (1.50:1). The proportion of rectal cancer 2000 - 2004 was 49.7%, significantly lower than that in 1985 - 1989 (64.8%), while the proportion of right hemi-colon cancer 2000 - 2004 was 28.7%, significantly higher than that in 1985 - 1989 (18.0%). The proportion of moderately and well differentiated cancer 2000 - 2004 was 80.6%, higher than that in 1985 - 1989 (70.1%), and the proportion of poorly differentiated cancer 2000 - 2004 was 19.4%, lower than that in 1985 - 1989 (29.9%). The proportion of colorectal cancer at Dukes A stage 2000 - 2004 was 9.8%, higher than that in 1985 - 1989 (3.2%). CONCLUSION: In the past 20 years, the incidence of colorectal cancer has increased in Guangdong province with a n increase of median age of incidence, The male to female ratio has decreased, and the incidence of right hemi-colon cancer, the rates of higher differentiated cancer and Dukes A stage cancer have increased.

[Clinical epidemiological characteristics of 3870 cases of colorectal cancers in Guangdong region].

OBJECTIVE: To explore the clinical characteristics and pattern of incidence of colorectal cancers in Guangdong region. METHODS: Analysis and summary were made for 3870 colorectal cancer patients pathologically confirmed in the Nanfang Hospital and Huizhou Municipal Central Hospital of Guangdong province. RESULTS: Median age of 3870 cases with colorectal cancer was 55.3. The high-risk age ranged from 41 to 70.204 cases among them were young patients (age < or = 30, 5.3%). With increase of age the number of cases with rectal cancers decreased gradually, while cancers occurring in the right hemi colon increased gradually. The ratio between male and female was 1.42:1. There were altogether 3958 colonic cancer lesions found in all the cases. Among them 3783 (97.8%) cases presented with a single lesson, 87 (2.2%) cases presented with multiple lesions. 2243 (56.7%) lesions located in the rectum, 717 (18.1%) in the left hemi colon, 998 (25.2%) in the right hemi colon. Histological types in all the lesions cases were grouped as follows: tubular adenocarcinoma 2943 (76.0%); papillary adenocarcinoma 256 (6.6%); mucinous carcinoma 425 (11.0%); and miscellaneous types 246 (6.4%). Colorectal cancers with poor differentiation occurring in the young were 38.2% while in the middle age and the elderly were 29.9% and 14.6%, respectively. The difference between two groups showed a statistical significance (P < 0.01). The cases with confirmed stage A, B, C and D were 234 (6.0%), 1936 (50.0%), 1310 (33.9%) and 390 (10.1%), respectively, according to Dukes' staging system. The cases with the progressing stages (B, C, D stages) were 3636 (94.0%) among all the cases. CONCLUSIONS: The number of patients with colorectal cancer admitted in hospital increased gradually in the recent 20 years, and showed a trend with the decrease percentage in rectal cancer and the gradual increasing in right hemi colon cancer with increase of patients age. Half of the colorectal cancer occurred in the rectum, the rest occurred in the left and right hemi colon. The three clinical epidemiological characteristics of colorectal cancer, which once existed in Chinese, has disappeared in Guangdong region.

[The risk factors and impact of gastroesophageal reflux disease on quality of life in general population].

OBJECTIVES: To assess the risk factors of gastroesophageal reflux disease (GERD) in the general population and its impact on health-related quality of life (HRQOL). METHODS: A face-to-face interview was carried out in Guangdong Province using a validated Chinese version Reflux Disease Questionnaire (RDQ) to assess the prevalence of GERD. Random clustered sampling of permanent inhabitants aged 18 to 90 years was carried out under stratification of urban and suburban areas. The impact of GERD on HRQOL was evaluated using the Chinese version of SF-36. The statistical analysis was performed with SPSS 10.0 programs. RESULTS: A total of 83 GERD patients were collected and 166 healthy subjects were selected as control. There was no difference in prevalence between male (2.6%) and female (2.4%). There was no significant association between age and prevalence of GERD symptoms. Divorced/widowed/separated subjects (OR 4.61) and subjects with severe working burden (OR 3.43) were significantly more likely to report GERD symptoms. As compared with the general population, subjects with GERD symptoms experienced considerable impairment in quality of life. CONCLUSIONS: Psychosocial factors may play important roles in the production of GERD symptoms. GERD has a negative impact on HRQOL.

[Tiam1 expression correlates with the biological behavior of human colorectal carcinoma cells].

OBJECTIVE: To investigate whether the Tiam1 gene expression enhances the invasive and metastatic capabilities of colorectal carcinoma cells. METHODS: Endogenous expression of Tiam1 in five colorectal carcinoma cell lines was investigated by RT-PCR. Tiam1/C1199HA cDNA was transfected into HT29, a colorectal carcinoma cell line without endogenous Tiam1 expression. RNA and protein expression of Tiam1 gene in the transfectants were detected by RT-PCR, immunohistochemistry and Western blot respectively. The biological behaviors of the transfectants were investigated by MTT and in-vitro invasion assays. RESULTS: Tiam1 gene was highly expressed in LoVo and SW620 cells. Low level expression was seen in HCT116 and SW480 and no expression was found in HT29. Transfection of Tiam1 significantly increased the proliferation of HT29 cells along with markedly enhanced in-vitro invasion and metastasis. CONCLUSIONS: Tiam1 gene plays an important role in the invasion and metastasis of colorectal carcinoma. It may be a useful marker for metastasis of colorectal carcinoma.

[Evaluation of the quality of life of patients with irritable bowel syndrome].

OBJECTIVE: To explore and assess the health-related quality of life (HRQOL) of irritable bowel syndrome (IBS) patients in the population. METHODS: Random clustered sampling involving permanent inhabitants aged 18 - 80 yr was carried out under stratification of urban and suburban areas in Guangdong Province. Altogether 231 IBS patients fulfilling the Rome II criteria and 636 Non-IBS as control were collected. The impact of IBS on HRQOL was evaluated using the Chinese version of SF-36. RESULTS: (1) There were no statistically significant differences between IBS and Non-IBS groups in aspects of sex, age educational level, and distribution according to areas (P > 0.05). (2) IBS patients reported significantly poorer HRQOL than controls (Non-IBS) on all SF-36 subscales (P < 0.05). The patients had poorer HRQOL than the Non-patients, but their differences weren't significant (P > 0.05). (3) The scores on all SF-36 subscales were highly associated with the frequency of abdominal pain in IBS patients (P < 0.05); They were also correlated to degree of effects of IBS symptoms on life reported by IBS patients (P < 0.05); The association between the scores and the symptom of fatigue which is the most extra-intestinal symptom in IBS was significant (P < 0.05); (4) Copying style was highly correlated to the eight SF-36 subscales; IBS still had a significant impact on patients after partialing out the effect of copying style. CONCLUSIONS: IBS symptoms had a negative impact on HRQOL and the SF-36 could be adopted to detect the differences between IBS group and Non-IBS group, which may be used as an outcome measure in future treatment studies. However, the development of IBS-specific measures of quality of life is necessary.

[A population-based epidemiologic study of irritable bowel syndrome in Guangdong province].

OBJECTIVE: To explore the prevalence of irritable bowel syndrome (IBS) and its risk factors in Guangdong province. METHODS: A questionnaire was used to screen IBS by face-to-face interviews according to Manning (modified including symptoms of constipation) and Rome II criteria. Random clustered sampling involving permanent inhabitants aged 18 - 80 years was carried out under stratification of urban and suburban areas. Potential risk factors were explored by comparing the frequencies among IBS group and non-IBS group using chi(2) and logistic analysis of multivariate adjusted for age and gender. RESULTS: A total of 4178 residents (male 1907, female 2271) were investigated. Mean age among the responders was (43 +/- 14) years. The response rate was 98%. The adjusted prevalence of IBS in Guangdong province is 5.67% according to the modified Rome II criteria, and is 11.50% according to Manning criteria. There is no difference between urban and suburban areas. The female was predominant in IBS, and the ratio of male to female was 1:1.25 (Rome II) and 1:1.34 (Manning). The age was poorly correlated with the prevalence. Events including history of analgesic use such as NSAID (OR = 3.83), history of food allergies (OR = 2.68), psychological distress (OR = 2.18), life events (OR = 1.89), history of dysentery (OR = 1.63) and negative coping style (OR = 1.28) are highly associated with IBS (P < 0.05). CONCLUSION: IBS is a common disorder in Guangdong Province which deserves greater care and further investigation.