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Including colon and rectal cancer, colorectal cancer (colorectal cancer, CRC) is the digestive system common malignant tumor. Its incidence in the worldwide incidence of malignancy in third place, second place in the Western developed countries, the incidence of malignant tumors. In our country, with the recent improvement of living standards are also increasingly higher incidence of colorectal cancer and diet changes, has leapt to Section 3-5 of the incidence of malignant tumors in China, and, according to forecasts of colorectal cancer morbidity and mortality in the future will continue to rise gradually. The colorectal treatment effect is not ideal, but is hard to implement effectively the cause of prevention. However, because colorectal precancerous lesions and early lesions more obvious, and the time for more than ten years, its screening and early diagnosis, early treatment possible. In recent years, research has been to clarify the incidence of colorectal cancer development is a multi-step, multi-factor, a variety of genetically modified synergies process. In these processes, the regulation of cell gene expression procedures are often changed. Epigenetic modification is one of the important ways of gene changes. Epigenetics (epigenetics) that do not involve changes in the DNA sequence of the genome and genetic modification of the genome to daughter cells during cell division can. DNA methylation and histone acetylation is an epigenetic modification of the main ways. Malignancy due to changes in DNA methylation is often an early event in the development process easy detection of colorectal cancer patients exfoliated cells DNA was found, so the detection of DNA methylation status change may be able to serve as a new diagnosis of colorectal cancer , which for colorectal cancer screening and early diagnosis. TFPI (tissue factor pathway inhibitor, TFPI2) gene encodes a product is a broad-spectrum serine protease inhibitor, is widely distributed in the normal human liver, pancreas, kidney, heart, skeletal muscle and prostate tissue in vitro strongly inhibited plasmin, trypsin, matrix metalloproteinase 1 (matrix metalloproteinases, MMP-1) and 3 (MMP-3) activation involved in extracellular matrix (extracellular matrix, ECM) remodeling process, the maintenance of the ECM structural integrity regulation of tumor cell invasion and metastasis, play an important role in tumor cell invasion and metastasis, and a series of physiological and pathological processes. From the level of transcription when TFPI2 gene promoter region methylation to cut TFPI2 gene expression, thereby reducing the ability of the regulation of tumor cell invasion and metastasis, and promote the development of malignancies. The purpose of this article using methylation-specific PCR (methylation-specific PCR, MSP) technology the feces analysis of 30 cases of colorectal cancer patients and 30 normal controls were TFPI2 gene methylation status, and with a stool specimens by immunochemical method fecal occult blood test, used to compare and evaluate the method detection TFPI2 gene methylation status change as the feasibility of noninvasive diagnostic method of colorectal cancer. Materials and Methods admitted to the First Affiliated Hospital of Zhengzhou University, from May 2009 to September 2009, 30 patients with colorectal cancer study, which were confirmed by surgery or endoscopy pathologically confirmed. 30 patients with colorectal cancer, 17 males and 13 females, the male to female ratio was 1.3:1, and the age range of 21-82 years old, with an average age of 57 years. Another 30 age-matched healthy people the normal control group, colonoscopy shows the full colonic mucosa found no abnormalities. Normal control group of 15 males and 15 females, the male to female ratio is 1:1, with an age range of 32-79 years old, with an average age of 54 years. Stool specimens collected before surgery or endoscopy ago, immediately collected and sent to the laboratory at -70 ℃ refrigerator. All of the subjects were hospitalized or outpatient visits immunochemical detection of fecal occult blood. After pretreatment of the specimen using the QIAamp DNA Stool Mini kit (QIAGEN, Germany) kit, DNA was extracted and saved at -20 ℃. Then in accordance with the operating instructions of The MethylampTM One-Step DNA Modification Kit (EPIGENTEK, USA) kit, bisulfite modification of DNA and purified, and placing a -70 ° C refrigerator standby. To re-bisulfite modified DNA as methylation-specific PCR template to detect TFPI2 gene methylation status. The experimental results using SPSS17.0 statistical software processing, gene frequency by direct counting among groups rate compared using the X2 test. Test results to P lt; 0.05 considered statistically significant. 1 in 30 cases of colorectal cancer patients stool specimens, 19 cases (63.3%) specimens detected TFPI2 gene promoter methylation, and the stool samples of 30 normal controls who had no one cases detected TFPI2 gene promoter methylation. 230 patients with colorectal cancer, 11 cases of fecal occult blood test was positive (36.7%), and 11 cases of occult blood positive results faeces of patients with colorectal cancer TFPI2 gene methylation test results were positive. TFPI2 methylation detection and diagnosis of colorectal cancer detection rate (63.3%) with the fecal occult blood test for the diagnosis of colorectal cancer detection rate (36.7%) compared with X2 = 4.267, P lt; 0.05 3TFPI2 gene methylation status change with the patient's sex, age and tumor location no significant correlation (P value gt; 0.05). Of 4TFPI2 gene promoter methylation in Dukes stage A, B, and C, D midterm incidence of 47.1% and 84.6%, respectively, a significant difference (P lt; 0.05); Secondly, poorly differentiated tumors TFPI2 gene promoter methylation incidence of 100%, well-differentiated tumors TFPI2 gene promoter methylation was 47.6%, the difference was very significant (P lt; 0.05). The conclusion 1TFPI2 gene methylation is colorectal cancer patients with fecal shedding common epigenetic changes in cells, and to prompt TFPI2 as a tumor suppressor gene, may become one of the non-invasive method of diagnosis of colorectal cancer molecular markers. Positive status 2TFPI2 gene methylation is no significant correlation with colorectal cancer patient's age, gender and tumor site. Significant correlation between methylation positive of 3 TFPI2 genes state with Dukes stage colorectal cancer patients and tissue differentiation.
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