Identification of lncRNA FAM83H-AS1 as a novel prognostic marker in luminal subtype breast cancer

Background: Luminal subtype breast cancer accounts for a predominant number of breast cancers. Considering the heterogeneity of the disease, it is urgent to develop novel biomarkers to improve risk stratification and optimize therapy choices. Long non-coding RNA (lncRNA) represents an emerging and understudied class of transcripts that play a significant role in cancer biology. Growing knowledge of cancer-associated lncRNAs contributes to the development of molecular markers for prognosis evaluation and gene therapy. Materials and methods: Three pairs of primary luminal subtype breast cancer tissues and adjacent non-cancerous tissues were collected and sequenced. EBseq algorithm was used to identify differentially expressed lncRNAs. RNA sequencing data from The Cancer Genome Atlas (TCGA) database were used to validate the robustness of our RNA-seq results. Kaplan-Meier and Cox regression analyses were utilized to assess the association between the lncRNAs and overall survival of patients in TCGA cohort. Results: A total of 796 lncRNAs were significantly dysregulated in luminal subtype breast cancer, including 436 upregulated and 360 downregulated lncRNAs. Among them, FAM83H antisense RNA 1 (FAM83H-AS1) was the most upregulated lncRNA, whereas GSN antisense RNA 1 (GSN-AS1) was the most downregulated lncRNA. Moreover, we proved that the high expression level of FAM83H-AS1 indicated unfavorable prognosis not only in luminal subtype breast cancer but also in all subtype breast cancers. To the best of our knowledge, this is the first report indicating that FAM83H-AS1 was involved in luminal subtype breast cancer and was an independent prognostic indicator. Conclusion: Our study provides a rich resource to the research community for further identifying lncRNAs with diagnostic and therapeutic potentials and exploring biological function of lncRNAs in luminal subtype breast cancer.