Through our analysis of lncRNAs in LSR breast cancer, we prioritized the most up-regulated lncRNA, LINC00355. Notably, LINC00355 was previously reported to promote proliferation in multiple cancer types including bladder cancer, colorectal cancer, prostate cancer, lung adenocarcinoma, and head and neck squamous cell carcinoma43,45–47,57–59 and induce epithelial to mesenchymal transcription, and serve as a diagnostic biomarker in colon cancer45–47,57–60; however, it has not yet been identified in breast cancer and identified here specifically in ER + late-stage relapse breast cancer. This evidence concerns the gene ESR1 and cancer.