Detection of cancer cells in peripheral blood of stomach cancer patients using RT-PCR amplification of tumour-specific mRNAs

Background: RT-PCR amplification of tumour-specific mRNA has been used for the detection of cancer cells in peripheral blood. Aim: To evaluate the characteristics of the tumour specific mRNA species in peripheral blood of stomach cancer patients. Methods: We analysed CEA, GalNAc-T, MUC-1, c-MET and hTERT mRNA expression in the stomach cancer cell lines and tissues, lymph nodes and peripheral blood of stomach cancer patients using RT-PCR. Results: In RT-PCR analysis of the peripheral blood, 4%, 8%, 21%, 46%, and 100% of stomach cancer patients were positive for CEA, GalNAc-T, c-MET, hTERT and MUC-1 mRNA, respectively, but MUC-1 mRNA was also positive in all normal blood samples. The detection of hTERT mRNA was correlated with poor differentiation (P =0.01) and lymph node metastasis (P =0.009). The presence of c-MET mRNA was correlated with T stage (P =0.025), lymph node metastasis (P =0.036), distant metastasis (P =0.031), and stage of the stomach cancer (P =0.023). Conclusions: Our study suggest that hTERT mRNA in peripheral blood can be a molecular marker for gastric cancer. We also showed that each molecular marker can be correlated with the clinicopathological features of the patients.