Expression Of Carcinoembryonic Antigen MRNA In Peripheral Blood Cells In Patients With Colorectal Cancer And Its Clinical Significance

Objective: Colorectal cancer is one of the most common malignancies with high incidence rate. Due to the progress made in diagnostic and therapeutic techniques, the prognosis of patients with colorectal cancer has improved in recent years, even about 30-50% of patients with no evidence of metastasis on the time of diagnosis have recurrences in less than 5 years after radical resection for the primary tumor. The sensitive PCR technique was used in the late 1980s. It has greatly facilitated the detection on occult cancer cells. Reverse transcription-PCR(RT-PCR) is applied to detect CEA mRNA expression of cancer cells in the blood of cancer patients, which can forecast the prognosis and monitor the efficiency of therapy. The present study is to investigate the carcinoembryonic antigen(CEA) mRNA expression in blood from patients with colorectal cancer and to evaluate its clinical significance.Methods: Peripheral blood samples are collected from 60 patients with colorectal cancer and 40 patients with colorectal polyp and 40 healthy volunteers . According to Dukes stage, the patients are divided into Dukes A(10), B(19), C(16), D(15). Other factors such as different kinds of pathological or the site of the tumor are also taken into account. Among 15 patients with Dukes D stage, metastasis of liver(9 cases) are discovered. CEA mRNA is detected by reverse transcription polymerase chain reaction (RT-PCR) and serum CEA is detected by Enzyme-linked immunosorbent assay. X2 analysis is used as the statistics method in this protocol.Results: The production of RT-PCR is analyzed by agarose gel electrophoresis. CEA mRNA molecular weight is standardized by markers in the position of 300bp. CEA positive is determined above 5ng/ml. The positive rate of CEA mRNA expression in blood samples of 60 patients with colorectal cancer is 68.3%. And one of the healthy volunteers is positive. But three of the 40 patients with colorectal polyp(7.5%) arepositive. The positive rate increases with the pathological staging and liver metastasis, but there are no significant relations between the rate and the malignant extent of cell differentiation.Conclusion: The expression of CEA mRNA in peripheral blood cells correlates with the pathological staging and liver metastasis of colorectal cancer, and it could be of potential use to monitor the micrometastases of tumor.