Characteristics of chromosomal instability‑related lncRNAs associated with progression and prognosis in breast cancer

Chromosomal instability (CIN), which leads to structural and numerical variations in chromosomes, plays an important role in the oncogenesis and progression of cancers. However, the functional role of CIN‑associated long non‑coding RNAs (lncRNAs) remains to be fully elucidated. Copy number variations and CIN were evaluated on the basis of aneuploidy and 70‑gene CIN‑signature scores. A CIN‑based prognostic model was constructed using univariate and multivariate Cox regression analyses. The performance of the CIN‑associated lncRNA signature was assessed using receiver operating characteristic curves and overall‑survival analyses. In vitro functional experiments of the lncRNA U62317.4 were conducted via ethynyldeoxyuridine, wound healing and invasion assays, as well as western blot analysis. The basal‑like subtype of breast cancer cells presented the highest frequency of copy number variations. The risk score model based on the 12 CIN‑related lncRNAs presented an improved prediction of overall survival in both the training and testing cohorts. Patients in the high‑risk group demonstrated a lower overall survival rate than those in the low‑risk group. Notably, U62317.4 was significantly upregulated in breast cancer (BC) tissues and cells compared with normal tissues. U62317.4 regulated breast cancer cell proliferation and migration and modulated CIN features by regulating key mitotic‑related proteins, such as p53, cell division cycle protein 20 and mitotic checkpoint serine/threonine‑protein kinase BUB1β. The present study revealed a predictive signature of prognosis in patients with breast cancer based on CIN scores, and the identified lncRNAs related to CIN demonstrated potential to serve as prognostic biomarkers. The functional role of U62317.4 provided notable insights into the underlying mechanisms and therapeutic targets of BC progression.