The human genome encodes ~16,000 long ncRNA (lncRNA) genes. Several lncRNAs participate in vital cellular functions, including cell proliferation and differentiation. A significant number of lncRNAs are deregulated in all types of cancer, including breast cancer (BC). Few of these lncRNAs are shown to regulate key biological processes, controlling cancer cell functions. Our laboratory is keen to understand the molecular function of lncRNAs that are deregulated in BC, especially in triple-negative breast cancer (TNBC) or basal-like subtype, which is considered to be the most aggressive subtype among all of the BC sub-groups. By performing high throughput transcriptome analyses in TNBC progression cell lines, we identified nearly one hundred lncRNAs, which show altered expression in both TNBC cell lines and patient samples. The abundant nuclear-localized MALAT1 lncRNA is one of the top candidates that showed elevated expression in BC cells and patients. We demonstrated that MALAT1 plays essential role in tumor progression and metastasis. Mechanistic studies revealed that MALAT1 promotes tumor progression and metastasis by modulating the pre-mRNA splicing of several oncogenic and tumor suppressor genes. We seek to determine the molecular function of BC-deregulated lncRNAs such as MALAT1, and identify their involvement in BC progression and metastasis.