Priya Singh

Breast cancer remains one of the leading causes of cancer-related morbidity and mortality among women . Research has elucidated numerous genetic and environmental factors contributing to its onset and progression, recent attention has turned to the role of mitochondrial genetics and dysfunction in cancer biology. Among various components of mitochondrial DNA (mtDNA), the 7S DNA—a short, single-stranded DNA segment within the displacement loop (D-loop) region—has emerged as a potential player in mitochondrial genome regulation and, cancer pathogenesis. The mitochondrial D-loop is a critical non-coding region involved in the initiation of replication and transcription of mtDNA. The 7S DNA, typically around 650 nucleotides in length, forms a triple-stranded structure in this region and is thought to regulate mitochondrial replication and transcription through complex mechanisms that are not yet fully understood. Alterations in 7S DNA content or structure can influence mitochondrial biogenesis, reactive oxygen species (ROS) production, and overall mitochondrial function—factors known to play pivotal roles in cancer development. In breast cancer, mitochondrial dysfunction is frequently observed and has been linked to altered energy metabolism, evasion of apoptosis, and increased oxidative stress, all of which are hallmarks of cancer progression. Reduced levels of 7S DNA have been associated with compromised mitochondrial function, potentially promoting a tumorigenic phenotype. Conversely, elevated 7S DNA levels may reflect heightened mitochondrial replication or stress responses, indicative of the metabolic reprogramming characteristic of cancer cells. Despite its small size, 7S DNA could serve as a valuable biomarker for mitochondrial health and disease progression in breast cancer. Its dynamic regulation may offer insights into the metabolic state of tumor cells and provide novel targets for therapeutic intervention. Understanding the precise role of mitochondrial 7S DNA in breast cancer progression is therefore a promising area of research with significant implications for early diagnosis, prognosis, and treatment of breast cancer.