65 Background: Detection of circulating tumor cells (CTC) in peripheral blood is thought to be a promising method to evaluate the extent of minimal residual disease that may be useful for predicting recurrence and for monitoring treatment efficacy. However, unlike breast or lung cancer, little information is available in patients with gastric cancer. Among them, evaluation of survivin, a member of the inhibitor of apoptosis (IAP) family, mRNA expression in peripheral blood appears to be a promising procedure with relative good performance for predicting recurrence after curative resection. In order to evaluate the clinical significance of surviving expression in peripheral blood, we performed real-time RT-PCR analysis using whole blood obtained from patients with gastric cancer. Methods: A total of 95 patients with gastric cancer treated at our cancer center between Nov. 2009 and Aug. 2012 were enrolled in this study. Peripheral blood samples were collected using PAX gene and RNA was isolated using Boom method. After cDNA synthesis, quantitative real-time PCR targeting survivin gene was performed. The relative expression level of survivin mRNA was calculated with actin beta as an internal standard. Correlation between survivin expression and clinicopathologic factors was investigated. Results: Survivin mRNA expression level in peripheral blood ranged from 34.8 to 1889.6, and the median level was 370.3. Survivin mRNA level tended to be higher in patients with T4, N3b, CY1, and Stage IV. There was no significant correlation with histological type, lympho-vascular invasion, or macroscopic type. If we set a cut-off value at 540, survivin was positive in 27 patients (28%). Disease-free survival was significantly worse in survivin positive patients than in negative patients (p=0.0216). Conclusions: Survivin expression in CTC was higher in advanced stage and appears to be a good prognostic marker in patients with gastric cancer. Validation with large sample size should be performed to confirm the significance of survivin in CTC.
Combination of four gene markers to detect circulating tumor cells in the peripheral blood of patients with advanced lung adenocarcinoma using real-time PCR
