Background: Recently, several reverse transcription-polymerase chain reaction (RT-PCR) techniques have been proven to be useful in the detection of circulating tumor cells (CTCs) in cancer patients. We attempted to detect CTCs in patients with gastric cancer (GC) using a RT-PCR assay for c-Met and MUC1 and to evaluate their clinical value.
Methods: Using a RT-PCR assay, c-Met and MUC1 mRNAs were amplified in 52 GC patients and 36 healthy individuals. Analyses were carried out for their correlation with the patients' clinicopathologic features, the occurrence of new post-operative metastasis, as well as the overall survival rates.
Results: In the RT-PCR analysis of peripheral blood, 61.5% (32/52) and 71.2% (37/52) of GC patients were positive for c-Met and MUC1 mRNA, respectively. The sensitivity and specificity of either mRNA detected in peripheral blood is 82.7% and 86.1%, respectively, with an accuracy of 84.1%. The detection of c-Met or MUC1 mRNA was significantly correlated with the depth of tumor invasion, lymph node metastases, TNM stage, vessel invasion, perineural involvement, and post-operative metastasis (all P<0.05). Kaplan-Meier analysis demonstrated that the overall survival rate of patients with positive c-Met or MUC1 mRNA expression in the peripheral blood was significantly shorter than in patients negative for c-Met or MUC1 mRNA expression (both P<0.05).
Conclusions: Our findings suggest that using RT-PCR for the detection of c-Met or MUC1 mRNA may be a promising tool for the early detection of micro-metastatic CTCs in GC patients. Combination of these 2 tumor-specific mRNA markers would increase the detection rate and may be clinically helpful in predicting the outcome in GC patients.