Abstract 3988: MicroRNA expression associated with response grade in gastric cancer patients’ tumors

Abstract

Abstract Background: Many chemotherapy schemes have been used in neoadjuvant treatment scenario to improve the overall and disease-free survival of gastric cancer (GC) patients treated with surgery alone. However, in some cases, the objective clinical response is not achieved, and this lack of response to neoadjuvant chemotherapy may delay curative surgery and increase surgical complications. Therefore, a major challenge for improving clinical outcomes is to understand the molecular mechanisms that may play essential roles in patients responses of GC treatments. The expression levels of several miRNAs have been found to be correlated with GC prognosis and could determine the clinical response for neoadjuvant chemotherapy. Therefore, our goal was to analyze the relation between miRNA profile and the pathological response grade of GC patients tumors treated with neoadjuvant chemotherapy or surgery alone. Methods: We selected 34 biopsy tumor samples of patients treated with neoadjuvant chemotherapy (collected before the treatment) and 23 tumor samples of patients submitted to surgery without adjuvant treatment. All patients treated with neoadjuvant chemotherapy received ECF, DCF or ECX prior the surgery, and subsequently they were submitted to a complete resection. The identification of differentially expressed miRNAs was done by TLDA Quantitative Real Time PCR. Results: After categorizing neoadjuvant chemotherapy patients according to percentage of viable tumor cells present in gastric resection and the surgical patients according to their 5 years of follow up status we could segregate those with and without response for both treatments. The comparison between response grade versus miRNAs showed 9 and 14 downregulated miRNAs in samples of patients without response for neoadjuvant chemotherapy and surgery alone, respectively. We also could observe 3 common downregulated miRNAs between patients without response in both groups. Conclusion: We identified some downregulated miRNAs involved in gastric cancer pathways and mechanisms of drug resistance that should manage to determine a predictable miRNA signature to perform a correct patient selection for GC treatments. Note: This abstract was not presented at the meeting. Citation Format: Michelle Maccarini Barcelos Baldoni, Cláudia Malheiros Coutinho Camillo, Renato David Puga, Maria Dirlei Ferreira Begnami. MicroRNA expression associated with response grade in gastric cancer patients’ tumors. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3988. doi:10.1158/1538-7445.AM2015-3988