Background: Survivin is an inhibitor of apoptosis and specifically expressed in several human cancers. The purpose of this study was to evaluate if there is a difference in the level of Survivin mRNA expression between different histological types of esophageal cancer. Furthermore we evaluated if a potential postresectional decrease in Survivin mRNA expression might be used to verify complete surgical resection and if neoadjuvant chemoradiation would influence these results.
Materials and Methods: Blood samples were obtained from 62 patients who were scheduled for surgical resection. 25 (40.3 %) patients had squamous cell carcinomas and 37 (59.7 %) adenocarcinomas. In 24 (38.7 %) patients neoadjuvant chemoradiation was performed for locally advanced disease. Whole blood was drawn one day preoperatively and 10 days post resection in all patients. The tumor cells were enriched from whole blood by density gradient centrifugation (OncoQuick®, Hexal, Frickenhausen) and total cellular RNA was extracted. Direct quantitative real-time reverse transcriptase PCR (RT-PCR, TaqMan™) assays were performed in triplicates to determine Survivin mRNA expression levels.
Results: Survivin mRNA expression in peripheral blood was detected in 50/62 patients (80.6 %). There were no significant differences in preoperative mRNA levels between squamous cell carcinomas and adenocarcinomas (p = 0.26). Postoperative Survivin levels were significantly lower than preoperative levels in 41.2 % of resected patients. In patients receiving neoadjuvant chemoradiation a decrease in the postoperative Survivin mRNA expression level was detected at 83.3 % of patients with adenocarcinomas compared to 50 % with squamous cell cancer (Mann-Whitney test: p < 0.04).
Conclusions: Our results demonstrate that direct real-time quantitative RT-PCR analysis of Survivin mRNA expression without prior nested PCR is technically feasible following tumor cell enrichment from whole blood samples in patients with esophageal cancer. Survivin levels were significantly reduced following surgical resections and might become a molecular marker for completeness of resection (molecular R0 marker). Survivin levels particularly decreased in adenocarcinomas following neoadjuvant chemoradiation and surgical resection.