Abstract
Abstract Uveal melanoma (UM) is a highly aggressive eye cancer that leads to metastatic death in up to half of patients. UMs can be divided into two prognostic groups based on their gene expression profile (GEP). The class 1 GEP is associated with low metastatic risk and the class 2 GEP with high metastatic risk. Class 1 tumors are associated with EIF1AX or SF3B1 mutations while Class 2 tumors are associated with inactivating mutations in the tumor suppressor BAP1. Class 1 and Class 2 UMs have been shown to differ in their expression of numerous known micro-RNAs and long non-coding RNAs (lncRNA). Here, we sought to identify novel differentially expressed lncRNAs using a publicly available RNA-Seq database. Raw RNA-Seq fastq files from 80 TCGA UM samples were obtained from the Cancer Genomics Hub (CGHub), quality controlled using FastQC (v0.11.3), and trimmed using trim-galor (v0.4.1). Sequences were aligned to the human genome (GRCh38) and accompanying general transfer format file (gtf) (Gencode v28) using STAR (v2.5). Transcript discovery was performed using Cufflinks (v2.2.1). Protein coding probability was calculated using CPC (v2.0), and transcripts predicted to be non-coding with transcript length >200bps were retained. 1671 novel transcripts were added to the gtf file, and fastq files were realigned with the new annotation. Estimated counts for all known and novel transcripts were generated using RSEM (v1.3.0) after STAR alignment. A cutoff of RPKM > 1 in at least 35% of tumors was used as a threshold for transcripts of interest, resulting in 61 novel transcripts, 32 of which were differentially expressed at FDR < 0.05 between Class 1 and Class 2 tumors, including 7 upregulated and 25 downregulated in Class 2 tumors. Further work is underway to elucidate the function of these novel transcripts in UM pathogenesis. Citation Format: Daniel A. Rodriguez, Jeffim N. Kuznetsov, Margaret I. Sanchez, Stefan Kurtenbach, J. William Harbour. Novel expressed long non-coding RNAs in uveal melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4244.
