Detection Of Guanylyl Cycalase C MRNA In Peripheral Blood From Patients With Colorectal Cancers And Its Significance

Background: Colorectal carcinoma is one of the most common human cancers. At present the major treatment to the colorectal carcinoma is radical surgery, but 30% to 50% of the patients after radical surgery had metastases and recurrence, which is the leading cause of death, and metastases could not be found in those patients before and after radical surgery by routine examination such as surgical exploration, B-ultrasound, CT, pathological slices and so on. Therefore, the micro-metastasis is an objective reality. The early detection of micro-metastases is of great significance of cancer diagnosis, staging, recurrence and prognosis, after-comprehensive treatment of choicePurpose: To detect the expression of the guanylate cyclase C mRNA (GCC-mRNA) in the blood of colorectal cancer patents and study its value in the diagnosis of micro-metastases, to explore the relation between guanylate cyclase C and colorectal cancer recurrence or metastasis.Method: To culture colon cancer cells in vitro and 20 cases of micro-metastases model were made by mixture of colon cancer cells with 5 ml blood of healthy population. To detect the expression of the guanylate cyclase C mRNA (GCC-mRNA) in these cases. At the same time 5 ml blood specimens of 40 colorectal cancer patients before surgery were collected, which were hospitalized during January 2007 to December 2007 in the first and second affiliated hospital of Nanchang University, Reverse transcription-polymerase chain reaction was employed to test the expression of GCC-mRNA, and 20 cases of healthy persons and 20 cases of benign disease in gastroenterology were used as controls.Result: The expression rate of GCC-mRNA was significantly higher in the micro-metastases models (85%,17/20) than that (0,0/20) of 20 healthy persons(P<0.01). The expression rate of GCC-mRNA was significantly higher in the colon cancer patients (57.5%,23/40) than that (20%,4/20) of 20 cases of benign disease in gastroenterology (P<0.01).There were no significant difference of GCC mRNA expression rate in age,gender and Dukes stage.(P>0.05). Conclusion:1 The GC-C-positive rate detcted in micro-metastases models is high and specificity, prompted by RT-PCR test GC-C colorectal cancer diagnosis of viable micro-transfer method, the results are reliable. 2 Colorectal cancer in patients with a higher GC-C positive rate, suggesting that colon cancer patients with high-transfer rate.3 The GC-C-positive rate is higher than the CEA expression in patients with colorectal cancer that GC-C-transfer for colorectal cancer diagnosis is better than the CEA.4 Detection of GC-C by RT-PCR is hope for the diagnosis of the metastases of colorectal cancer.