Novel Genes Closely Adjacent To And Coexpressed With Esr1 Affect Proliferation In Er Plus Ve Breast Tumors

Background: Approximately 80% of human breast carcinomas present as estrogen receptor α-positive (ER+ve) disease and ER status is a critical factor in treatment decision-making. However, ER+ve tumors are heterogeneous in both their molecular profiles and response to therapy. Up to 50% of patients derive little or no clinical benefit from treatment and many exhibit de novo or intrinsic resistance to hormonal therapy. Aim: To investigate factors associated with the level of expression of the ER gene that may be potential determinants of the biology of ER+ve tumors. Methods: Pre- and 2wk post-anastrozole tumor biopsies were obtained from 104 postmenopausal women with stage I to IIIB ER+ early breast cancer. RNA extracted from biopsies was analyzed on Illumina 48K microarrays and quantitative trait analysis by Spearman correlation was used to identify genes whose expression in tumors correlated significantly with ESR1. Results: Expression of three previously uncharacterized open reading frames (ORFs) located immediately upstream of ESR1 on chromosome 6q21, RMND1, C6ORF97 and C6ORF211, were highly correlated with ESR1 (Rs=0.672, 0.637 and 0.546 respectively, p Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2916.