Down-regulation of Wnt Antagonist,SFRP1 in Colorectal Tumorigenesis

OBJECTIVE To assess the functional change of SFRP1 （secreted frizzled-related protein1）, in colorectal tumorigenesis. METHODS Immunohistochemical investigation and the semiquantitative reverse transcription-polymerase chain reaction （RT-PCR） were used to assess the expression of SFRP1, β-catenin （β-cat） and E-caderin （E-cad） in matched samples of normal colorectal mucosa, adenomas and cancers. RESULTS SFRP1 mRNA expression was down-regulated in the neoplasms, and abnormal expressions of β-cat and E-cad were found in colorectal adenomas and colorectal cancers. CONCLUSION Down-regulation of SFRP1 observed is consistent with its acting as a tumor suppressor gene in colorectal tumorigenesis.

Risk of colorectal neoplasm in patients with acromegaly: A meta-analysis

AIM: To examine the risk of colorectal neoplasm in acromegalic patients by meta-analyzing all relevant controlled studies. METHODS: Extensive English language medical literature searches for human studies, up to December 2007, were performed using suitable keywords. Pooled estimates [odds ratio (OR) with 95% confidence intervals (CI)] were obtained using either the fixed or random-effects model as appropriate. Heterogeneity between studies was evaluated with the Cochran Q test whereas the likelihood of publication bias was assessed by constructing funnel plots. Their symmetry was estimated by the adjusted rank correlation test. RESULTS: For hyperplastic polyps the pooled ORs with 95% CI were 3.557 (2.587-4.891) by fixed effects model and 3.703 (2.565-5.347) by random effects model. The Z test values for overall effect were 7.81 and 6.984, respectively (P < 0.0001). For colon adenomas the pooled ORs with 95% CI were 2.486 (1.908-3.238) (fixed effects model) and 2.537 (1.914-3.364) (random effects model). The Z test values were 6.747 and 6.472, respectively (P < 0.0001). For colon cancer the pooled OR with 95% CI was identical for both fixed and random effects model (OR, 4.351; 95% CI, 1.533-12.354; Z = 2.762, P = 0.006]. There was no significant heterogeneity and no publication bias in all the above meta-analyses. CONCLUSION: Acromegaly is associated with an increased risk of colorectal neoplasm.

Prospective cohort comparison of flavonoid treatment in patients with resected colorectal cancer to prevent recurrence

AIM: To investigate biological prevention with flavonoids the recurrence risk of neoplasia was studied in patients with resected colorectal cancer and after adenoma polypectomy. METHODS: Eighty-seven patients, 36 patients with resected colon cancer and 51 patients after polypectomy, were divided into 2 groups: one group was treated with a flavonoid mixture (daily standard dose 20 mg apigenin and 20 mg epigallocathechin-gallat, n = 31) and compared with a matched control group (n = 56). Both groups were observed for 3-4 years by surveillance colonoscopy and by questionnaire. RESULTS: Of 87 patients enrolled in this study, 36 had resected colon cancer and 29 of these patients had surveillance colonoscopy. Among the flavonoid-treated patients with resected colon cancer (n = 14), there was no cancer recurrence and one adenoma developed. In contrast the cancer recurrence rate of the 15 matched untreated controls was 20% (3 of 15) and adenomas evolved in 4 of those patients (27%). The combined recurrence rate for neoplasia was 7% (1 of 14) in the treated patients and 47% (7 of 15) in the controls (P = 0.027). CONCLUSION: Sustained long-term treatment with a flavonoid mixture could reduce the recurrence rate of colon neoplasia in patients with resected colon cancer.

Gene expression profiling:Canonical molecular changes and clinicopathological features in sporadic colorectal cancers

AIM： To investigate alternative or subordinate pathways involved in colorectal tumorigenesis and tumor growth, possibly determining at-risk populations and predicting responses to treatment. METHODS： Using microarray gene-expression analysis, we analyzed patterns of gene expression relative to canonical molecular changes and clinicopathological features in 84 sporadic colorectal cancer patients, standardized by tumor location. Subsets of differentially expressed genes were confirmed by real-time reverse-transcript polymerase chain reaction （RT-PCR）. RESULTS： The largest number of genes identified as being differentially expressed was by tumor location, and the next largest number by lymphovascular or neural invasion of tumor cells and by mismatch repair （NMR） defects. Amongst biological processes, the immune response was significantly implicated in entire molecular changes observed during colorectal tumorigenesis （P 〈 0.001）. Amongst 47 differentially expressed genes, seven （PISD, NIBP, BAI2, STOML1, MRPL21, MRPL16, and MKKS） were newly found to correlate with tumorigenesis and tumor growth. Most location-associated molecular changes had distinct effects on gene expression, but the effects of the latter were sometimes contradictory. CONCLUSION： We show that several differentially expressed genes were associated with canonical molecular changes in sporadic colorectal cancers, possibly constituting alternative or subordinate pathways of tumorigenesis. As tumor location was the dominant factor influencing differential gene expression, location-specific analysis may identify location-associated pathways and enhance the accuracy of class prediction.

Comparison of virtual colonoscopy and colonoscopy in diagnosis of colorectal neoplasia

The diagnostic value of virtual colonoscopy versus colonoscopy was compared in detection of colorectal neoplasia. Virtual colonoscopy was performed on 29 patients with suspected colorectal diseases, Results were compared with colonoscopy for each case. Virtual colonoscopy was successfully performed on each patient. All patients tolerated virtual colonoscopy well, had no complications. All colorectal malignance were identified both by virtual colonoscopy and colonoscopy. Twenty-five polyps were detected with colonoscopy, whereas only 16 polyps were defined by virtual colonoscopy. Detection rates of polyps greater than 1.0 cm,between 0.5-0.9 cm and less than 0.5 cm in size were 90%,62.5% and 28.6% respectively. Virtual colonoscopy is fast, minimally invasive and well tolerated. This technique is a valuable clinical method in diagnosis of colorectal malignance and polyps larger than 0.5 cm in size.