Abstract 2992: The landscape of long non-coding RNAs in cancer

Abstract

Abstract Long non-coding RNAs (lncRNAs) are emerging as important players in cancer. The emergence of high-throughput RNA sequencing (RNA-Seq) technology provides a revolutionary means for systematic discovery of transcribed elements. However, efforts to catalog lncRNAs have thus far failed to appreciate the transcriptional robustness and complexity in the human genome because they were confined to select cell lines or small numbers of mostly normal tissue. In order to delineate genome-wide lncRNA expression, we curated 7,256 RNA-Seq libraries comprising over 43 terabases of sequence from 25 independent studies including tumors, normal tissues, and cell lines. The data were processed using ab initio transcriptome meta-assembly methodologies to develop a consensus of 91,013 expressed genes. Over 68% (58,648) of genes were classified as lncRNAs, of which 79% (48,952) were previously unannotated. About 1% (597) of the lncRNAs harbor ultraconserved elements and 7% (3,900) overlap disease-associated single nucleotide polymorphisms (SNPs). To prioritize lineage-specific, disease-associated lncRNA expression, we developed a non-parametric method for differential expression testing called Sample Set Enrichment Analysis (SSEA), and nominated 7,942 lineage- or cancer-associated lncRNA genes. In order to interrogate potential functionality for these lncRNAs, gene set enrichment testing was performed on genes correlated with each lncRNA. By uncovering this expansive landscape of cancer-associated lncRNAs, we provide the scientific community a powerful starting point to begin investigating their biological relevance. We anticipate that the lncRNAs identified by this study, as well as the computational tools developed herein, will provide a foundation for lncRNA genomics, biomarker development, and the delineation of cancer disease mechanisms. Citation Format: Yashar S. Niknafs, Matthew K. Iyer, Arul M. Chinnaiyan. The landscape of long non-coding RNAs in cancer. [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 2992. doi:10.1158/1538-7445.AM2015-2992