Study On Quantitative Analysis Of Carcinoembryonic Antigen Messenger RNA In Colorectal Cancer

Purpose:We want to establish the methods of quantitation of CEAmRNA in peripheral blood by competitive nested Reverse Transcriptase-Polymerase Chain Reaction in patients with colorectal cancer and determinate its sensitivity.Carcinoma tissue and peripheral blood of patients with colorectal cancer were detected to discuss clinical significance of sensitivity and specificity in earlier diagnosis and of assigning of prognosis by this examination.Material and Methods: We established the assay system to detect quantitivly CEAmRNA in peripheral blood of patients with colorectal carcinoma by utilizing the mutant fragment of competitor CEAmRNA with a new introduced restriction enzyme site .which was diluted in Series.Its sensitivity was checked out by using cell strain Lovo.The system was then used to assay the capacity of CEAmRNA of samples obtained from some Carcinoma tissue and lymph nodes, perioperative peripheral blood of patients with colorectal cancer .tissue and peripheral blood of patients with bengin disease in large bowel.The study was performed in relative property.Result:The sensitivity of this assay system is very high.A CEA-specific competitive nested RT-PCR can detect five CEA-positive cell in a background of 5 ml blood,giving a sensitivity ratio of 1:107.Of all histologically negative lymph nodes,CEAmRNA was proved in 35.7% of lymph nodes. The CEAmRNA level in neoplasms tissue of patients with colorectal carcinoma was not correlated with histological grading(P>0.05).The cut-off level ofCEAmRNA for relative discrimination between bengin diseases and malignant diseases in large bowel is 102copies/ugRNA.Overall positive rate of CEAmRNA in peripheral blood of patients with colorectal cancer was 75%.The assay of CEAmRNA level in peripheral blood is more sensitive and specific than that of CEA level in serum(P<0.01). There was a significant difference between preoperative and postoperative CEAmRNA level in peripheral blood(P<0.01).This demonstrates that operation is first choice to cure the patients with colorectal carcinoma.There was also a significant reduction in CEAmRNA level in peripheral blood after chemotherapy and radiotherapy(P<0.01).The combination therapy including chemotherapy and radiotherapy is the best assisted treatment after operation(P<0.05). It is also the best therapy in the treatment of nonhepatic intra-abdominal recurrences that possible radical resection will be performed at aids of combined chemotherapy and radiotherapy(P<0.001).Conclusion: The CEAmRNA level in peripheral blood of patients with colorectal cancer as an important marker has been confirmed in the field of earlier diagnosis, assessment of curative effect, assigning of prognosis and monitoring postoperative recurrences. In conclusion this method will play a significant role in monitoring peoples with high risk of CRC,patients after operation , in earlier diagnosis and in enhancing curative effect .