Abstract 4734: miR-9-5p expression in breast cancer correlates with hormone receptor status and affects patients survival

miR-9 (hsa-miR-9-5p, miR-9-5p) is a highly conserved microRNA (miRNA) primarily expressed in the central nervous system. The three promoters of miR-9 (miR-9-1 at 1q22, miR-9-2 at 5q14.3 and miR-9-3 at 15q26.1) are embedded within CpG islands, and hypermethylation in at least one of these regions has been reported in several tumor types, thus miR-9-5p has been designated as an epigenetically regulated miRNA. However, only a partial or none correlation between methylation status of miR-9 loci and miR-9-5p expression has been demonstrated so far. Furthermore, the expression levels of miR-9-5p resulted highly variable across different carcinomas and conflicting evidences also exist about its functional role within the tumor context. In light of this, we took the effort of clarifying the role of miR-9-5p in primary breast cancer tissues and of evaluating its potential as clinical relevant prognostic biomarker. We analysed miR-9-5p expression and miR-9 promoters methylation status in 129 breast cancer cases and 12 normal breast tissues (NBTs), by qRT-PCR and MSP respectively. Overall, miR-9-5p was increased in tumors compared to NBTs (P Citation Format: Raffaela Barbano, Barbara Pasculli, Michelina Rendina, Andrea Fontana, Caterina Fusilli, Massimiliano Copetti, Stefamo Castellana, Vanna Maria Valori, Maria Morritti, Paolo Graziano, Luigi Ciuffreda, Michelina Coco, Francesco Picardo, Tommaso Mazza, Ella Evron, Roberto Murgo, Evaristo Maiello, Manel Esteller, Vito Michele Fazio, Paola Parrella. miR-9-5p expression in breast cancer correlates with hormone receptor status and affects patients survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4734. doi:10.1158/1538-7445.AM2017-4734