Abstract 1505: Towards an understanding of the different expression profile of fibroblasts from distinct subtypes from breast cancer and normal mammary tissue assessed by transcriptome sequencing.
Authors: Natália Bromberg, Dirce Maria Carraro, Carlos Alberto Bragança Pereira, Gustavo Campos Molina, Mabel Gigliola Pinilla, Elisa Napolitano Ferreira, Maria Mitzi Brentani
Journal: Cancer Research (2013)

Abstract The highly heterogeneous clinical, histological, biological and genetic nature of breast malignancies is due in part to their extreme molecular complexity. During breast carcinogenesis, cancer associated fibroblasts (CAFs) have active role in the initiation, progression, metastasis and recurrence of tumors, which adds new levels of complexity to cancer biology, but also brings new prognostic and therapeutic opportunities. We implemented a pilot study to explore the postulation that CAFs within the stroma may exhibit specific gene expression profiles according to the carcinoma subtype. We enrolled frozen breast tissues from nine human breast samples representing three normal tissues, three luminal A and three triple negative subtypes. Fibroblasts were isolated by laser microdissection. For each subtype studied, a cDNA library was constructed and submitted to a transcriptome sequencing (RNA-Seq) on the Genome Sequencer FLX Titanium 454 Plataform. The generated data revealed a total of 14,950 transcripts sequenced and 10,586 genes identified (53.72% of the human genome repertoire). A list of 221 differentially expressed transcripts, obtained by pair wise comparisons among the 3 groups, was ranked by their probabilities of differential expression from 91%-100% (greater expression probability), and from 0.09-9.8% (lower expression probability). Functional similarity interactions (Fun-Net) were constructed using Gene Ontology (GO) annotations as defined in the Entrez Gene database to identify biological functions overrepresented. In addition, 36 differentially expressed genes were selected for technical and biological validation by RT-qPCR (Taqman Low Density Array - TLDA) and tissue microarray (TMA) techniques. Until now 10 out of 20 differentially expressed genes were validated by RT-qPCR. Considering the comparison between fibroblasts associated either to triple negative or luminal breast carcinoma subtypes, five differentially expressed genes were confirmed: S100A13, PPIA, HNRNP0, CUL3 and SLC25A32. Our results indicate that specific changes exist in CAFs derived from breast cancer subtypes, which in turn may contribute to each tumor subtype specific clinical behavior. Supported by FAPESP: 05/60333-7, 09/10088-7. Citation Format: Natália Bromberg, Dirce Maria Carraro, Carlos Alberto Bragança Pereira, Gustavo Campos Molina, Mabel Gigliola Pinilla, Elisa Napolitano Ferreira, Maria Mitzi Brentani. Towards an understanding of the different expression profile of fibroblasts from distinct subtypes from breast cancer and normal mammary tissue assessed by transcriptome sequencing. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1505. doi:10.1158/1538-7445.AM2013-1505