Correlated Analysis Of Expression Of Micro-RNA-21with Tumor Response After Neoadjuvant Chemotherapy In Advanced Gastric Cancer

Gastric cancer characterized by high mortality and morbidity is a kind of malignant tumor in China.Neoadjuvant chemotherapy is becoming the focus in gastric cancer treatment and has the potential to replace the current strategy. MicroRNA-21is one of the most important microRNAs and potentially plays important role in tumor cells proliferation, tumorigenesis and affects tumor response after chemotherapy.Objective:To analyze the impact of microRNA-21expression on treatment outcomes in locally advanced gastric cancer patients receiving preoperative S-1combined with oxaliplatin chemotherapy.Methods:Preoperative AJCC stage Ⅱ-Ⅲ gastric cancer patients received S-1(80mg/m2/day; days1-14) and oxaliplatin (130mg/m2; day1) every3weeks and subsequently received gastrectomy with D1/D2lymphadenectomy. We will collect serum and tumor tissues in gastric cancer patients after neoadjuvant chemotherapy and analyze the correlation of microRNA-21expression with tumor response using quantitative reverse-transcriptase polymerase chain reaction (RT-PCR).Results:Between January2013and January2014,104patients were enrolled in this study.78(75%) patients had clinical tumor response and52(50%) patients achieved histological response. The results showed that microRNA-21expression in tumor tissues was significantly higher in histological responders than non-responders (p=0.025). MicroRNA-21expression in serum was significantly lower in histological responders than non-responders (p=0.006).Similar results were not found when comparing microRNA-218and microRNA-223expression levels.Conclusion:Clinically, fluorouracil and platinum based neoadjuvant chemotherapy could downstage tumor size and reduce metastatic tumor cells in gastric cancer patients. MicroRNA-21expression in serum was significantly lower in histological responders than non-responders but was higher in tumor tissues. MicroRNA-21may be potential predictive treatment biomarkers in gastric cancer.