Copy number alterations: a catastrophic orchestration of the breast cancer genome.

Copy number alterations (CNAs) are prevalent across breast cancer (BCa) subtypes, with triple-negative BCa exhibiting the most heterogeneous CN profile, while luminal A/estrogen-receptor-positive tumors demonstrate the least heterogeneity. While chromosome arm-level CNAs impact 25% of the typical cancer genome, only 10% of the genome is affected by focal CNAs. The most frequent CNAs in BCa include losses of 8p, 13q, 16q, and 17p and gains of 1q and 8q. CNAs influence tumor biology, including cell proliferation, invasion, and metastasis. They can also serve as prognostic markers, with specific CNAs associated with disease aggressiveness and poor clinical outcomes. While CNAs offer promise as biomarkers for personalized treatments, challenges such as tumor heterogeneity and clonal evolution must be addressed. Technological advances and bioinformatics present opportunities for refining our understanding of CNAs and translating this knowledge into clinical practice. Breast cancer (BCa) is a prevalent malignancy that predominantly affects women around the world. Somatic copy number alterations (CNAs) are tumor-specific amplifications or deletions of DNA segments that often drive BCa development and therapy resistance. Hence, the complex patterns of CNAs complement BCa classification systems. In addition, understanding the precise contributions of CNAs is essential for tailoring personalized treatment approaches. This review highlights how tumor evolution drives the acquisition of CNAs, which in turn shape the genomic landscapes of BCas. It also discusses advanced methodologies for identifying recurrent CNAs, studying CNAs in BCa and their clinical impact. [ABSTRACT FROM AUTHOR]