Study On Detecting Colorectal Cancer Micrometastases In Lymph Nodes By Nested Reverse Transcriptase-Polymerase Chain Reaction Amplification Of Cytokeratin 20 And Matrix Metalloprotreinase-7

Objective To develop a nested reverse transcriptase polymerase chain reaction method to amplify Cytokeratin 20mRNA and Matrix Metalloproteinase-7mRNA for detecting colorectal cancer micrometastases in lymph nodes and to evaluate its specificity and sensitivity. Methods The RT-PCR system was set up by using nest primer. The presence of CK20mRNA and MMP-7mRNA was investigated by nested RT-PCR in 100 lymph nodes from 30 colorectal cancer patients who underwent curative operation. Tweenty-five lymph nodes from 10 patients with benign intestinal disease were served as negative control. The results of nested RT-PCR were compared with ones of routine histology. Results The positive rate of CK20mRNA and MMP-7mRNA in 187 lymph nodes from 30 colorectal cancer patients was 40. 11%(75/187), 51. 87%(97/187) respectively, while only 57 samples were histologically positive. The expression of CK20mRNA and MMP-7mRNA in 25 lymph nodes of 10cases of control group were all negative. Conclusion Nested reverse transcriptase - polymerase chain reaction was a sensitive and specific method to indicate the expression of CK20mRNA and MMP-7mRNA in lymph nodes as a helpful marker of micrometastases of colorectal carcinoma cells. It is superior to routine histopathological assay in examing lymph node metastases. The detection of CK20mRNA and MMP-7mRNA in lymph nodes may contribute to improve the accuracy of clinical staging, determine patients ' prognosis and provide information for adjuvant therapy.