Dysregulation of lncRNA LINC00968 may contribute to the tumorigenesis of estrogen receptor-positive (ER+) breast cancer

Abstract Background: Estrogen receptor-positive (ER+) breast cancer (BC) (luminal A and B subtypes) comprises up to 70% of all BC patients. LncRNAs can affect many biological and pathological processes, and dysregulation of them is related to human cancers. The potential role of lncRNA LINC00968 in ER+ BC is still unclear. Methods: We analyzed the LINC00968 expression across 44 paired luminal BC tissues from the TCGA-BRCA RNA sequencing dataset, and we used the GEPIA2 web server and GENEVESTIGATOR software, as well. The qRT-PCR assay was performed to confirm the LINC00968 expression in 71 paired luminal BC tissues and two luminal A cell lines (MCF7 and T47D). Moreover, to better understand the potential function of LINC00968 in luminal BC, multiple in silico data analyses have been done including co-expression, functional enrichment, and genetic alteration analyses. Results: The results of data analyses retrieved from BRCA dataset and databases revealed the significant downregulation of LINC00968 in luminal A and B BC. Also, the results of qRT-PCR in luminal BC tissues and cell lines confirmed the earlier data. LINC00968 expression was negatively associated with tumor stage and lymph node metastasis. Additionally, functional annotation analyses revealed that LINC00968 might be involved in vascular development and angiogenesis, extracellular matrix organization, and cell motility and migration. LINC00968 might have functions in some cancer-related signaling pathways, like the PPAR signaling pathway, small ligand GPCRs, etc. Conclusions: Our study found that LINC00968 may be a potential tumor suppressor gene in luminal BC. Downregulation of LINC00968 might promote tumorigenesis, invasion, and metastasis of luminal BC.