Abstract 4267: Gene expression profile of fibroblasts from different topographical origins in breast cancer patients
Authors: Paulo Roberto Del Valle, Maria Lucia Hirata Katayama, Patricia Bortman Rozenchan, Cintia Milani, Eduardo Carneiro Lyra, Renato Puga, Dirce Maria Carraro, M Mitzi Brentani, Maria Aparecida Azevedo Koike Folgueira
Journal: Cancer Research (2012)

Abstract Background: In breast cancer, there is increasing evidence that stromal cells, including fibroblasts, may influence tumor development in the primary site, as well as in regional and distant metastatic sites. Objectives: To compare fibroblasts from the primary tumor (PT), lymph nodes and bone marrow (BM) from breast cancer patients, by means of their expression profile. Methods: Fibroblasts primary culture was established from 14 breast cancer patients: PT (n=4), axillary nodes (3 from positive and 3 from negative nodes) and BM (2 with and 2 without micrometastasis, identified by RT-PCR for KRT19). Expression analysis was performed through a customized cDNA microarray platform (4,800 ORESTES) analyzed by SAM multiclass (TMEV; FDR 0%), followed by LIMMA test (p &amp;lt; 0.01 and fold change between groups ≤ 2). Functional analysis was performed using ToppGene Suite and Gene Set Enrichment Analysis (GSEA). Afterwards, fibroblasts from PT (n=5), nodes (n=13) and BM (n=4) were cultured and the expression of candidate genes was evaluated by RT-qPCR. Results: The expression profile of fibroblasts obtained from the three sites, analyzed by microarray, revealed 448 differentially expressed genes, which appropriately clustered fibroblasts in three different branches, in accordance with their topographical origin. GSEA identified enrichment in 74 genes sets (p &amp;lt; 0.01), 44 of them in the comparison of fibroblasts from nodes with BM, including negative regulation of transcription and negative regulation of biological process. Among differentially expressed genes in fibroblasts were: DUSP1, TGFB2, LOX, CYR61, PDK4, HNMT / MAPK13, MRPL37 (more and less expressed, respectively, in the BM); MXRA5, MSC / NOTCH2 (more and less expressed, respectively in the PT). No main transcriptional differences were found between samples from involved or uninvolved sites. Eleven genes were selected for further evaluation in newly cultured fibroblasts, using RT-qPCR, and expression of them, as evaluated by another methodology, could correctly discriminate the fibroblasts, according to their topographical origin. MAPK13, HNMT/MXRA5, PDK4, were confirmed more and less expressed, respectively, in fibroblasts from PT (vs BM); MRPL37 was less expressed in fibroblasts from BM (vs PT and nodes), and NOTCH2, was more expressed in fibroblasts from the nodes (vs PT). CYR6, LOX, MAPK13, MSC, NOTCH2, TGFB2 are linked within the same network (ToppGeneNet) and were all more expressed in fibroblasts from nodes vs PT. Despite these results, microarray and PCR data were not concordant for all genes. Conclusion: In breast cancer patients, fibroblasts obtained from different topographical regions present a differential gene expression profile, which may influence tumor behavior. Supported by FAPESP and CAPES Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4267. doi:1538-7445.AM2012-4267