Long non-coding RNAs in breast cancer metastasis.

Breast cancer is the leading cause of cancer-related death among women. Recurrence of primary tumor and
metastasis to distant body parts are major causes of breast cancer-associated mortality. The 5-year survival rate
for women with metastatic breast cancer is only 25–30%. Breast cancer metastasis is a series of processes
involved with EMT, invasion, loss of cell to cell adhesion, alteration in cell phenotype, extravasation, microenvironment of the tumor, and colonization to the secondary sites. Epigenetic modification is involved in the
transformation of the distant stromal cell into a secondary tumor. LncRNAs, are one the key epigenetic modifiers,
are the largest endogenous non-coding RNAs with approximate base-pair lengths from 200 nt to 100 kb. LncRNA
plays a crucial role in breast cancer metastasis by sponging miRNA, by degrading or silencing specific mRNA, or
else by targeting the enzymes and microprocessor subunits involved in the biogenesis of miRNA. LncRNA also
alters the expression of several genes involved in breast cancer metastasis and modulating different cell signaling
pathways. The goal of this review is to provide a better understanding of the role of lncRNA in the regulation of
breast cancer metastasis. We also summarized some of the key lncRNAs that regulate the genes and signaling
pathways involved in breast cancer invasion and metastasis.