Background/Objectives: Triple-negative breast cancer (TNBC) is a highly aggressive subtype with limited therapeutic options, and identifying reliable biomarkers for diagnosis and prognosis is crucial for improving patient outcomes. Mitochondrial DNA (mtDNA) copy number has been linked to an increased risk of developing various types of cancer, including breast cancer. However, there is a lack of understanding regarding how mtDNA copy number variations may influence the development and progression of TNBC. Methods: This study investigated mtDNA copy number in TNBC tumors and corresponding normal breast tissues from 23 TNBC patients who received neoadjuvant chemotherapy. The relative mtDNA copy number was estimated using quantitative PCR for the NADH dehydrogenase subunit 1 (ND1) and subunit 5 (ND5) regions. Results: The results showed a significant decrease in mtDNA copy number in TNBC tumor tissues compared to corresponding normal breast tissue. However, no significant correlation was found between mtDNA content and clinical parameters such as age, tumor size, or chemotherapy response. Conclusions: These results suggest that while mtDNA content decreases in TNBC tumors, it may not directly influence these clinical characteristics. Despite some inconsistencies in the literature regarding mtDNA dynamics in cancer, this study supports the potential of mtDNA as a biomarker for TNBC. Larger cohort studies are needed to further validate these results and explore the role of mtDNA in guiding personalized treatment strategies for TNBC patients.

Aim: Duchenne Muscular Dystrophy (DMD) results in a deficiency of dystrophin expression in patient muscle fibers, leading to progressive muscle degeneration. Treatment of DMD has undertaken current transformation with the advancement of novel gene therapy and molecular biology techniques, which are secure, well-tolerated, and effective therapeutic approaches. Introduction: DMD gene therapies have mainly focused on young DMD patients as in vivo animal model trials have been performed in 0–1-month DMD mice. However, it has not yet been answered how micro-dystrophin encoding lentiviral treatment affects Dystrophin expression and DMD symptoms in 10-month mdx mice. Methods: We planned to integrate the micro-Dystrophin gene sequence into the muscle cells by viral transfer, using micro-Dystrophin-encoding lentivirus to reduce the dystrophic pathology in late-stage dmd mice. The histopathological and physiological-functional regeneration activities of the lentiviralmicro- Dystrophin gene therapy methods were compared, along with changes in temporal Dystrophin expression and their functionality, toxicity, and gene expression level. Results: Here, we showed that the micro-dystrophin transgene transfers intramuscularly and intraperitoneally in late-stage dmd-mdx-4cv mice restored dystrophin expression in the skeletal and cardiac muscle (p <0.001). Furthermore, motor performance analysis, including hanging and tracking tests, improved statistically significantly after the treatment (p <0.05). Conclusion: Consequently, this study suggests that patients in the late stages of muscular dystrophy can benefit from lentiviral micro-dystrophin gene therapies to present an improvement in dystrophic muscle pathology.

Pathogenic variations in the BRCA2 gene have been detected with the development of next-generation sequencing (NGS)-based hereditary cancer panel testing technology. It also reveals an increasing number of variants of uncertain significance (VUSs). Well-established functional tests are crucial to accurately reclassifying VUSs for effective diagnosis and treatment. We retrospectively analyzed the multi-gene cancer panel results of 922 individuals and performed in silico analysis following ClinVar classification. Then, we selected five breast cancer-diagnosed patients’ missense BRCA2 VUSs (T1011R, T1104P/M1168K, R2027K, G2044A, and D2819) for reclassification. The effects of VUSs on BRCA2 function were analyzed using comet and H2AX phosphorylation (γH2AX) assays before and after the treatment of peripheral blood mononuclear cells (PBMCs) of subjects with the double-strand break (DSB) agent doxorubicin (Dox). Before and after Dox-induction, the amount of DNA in the comet tails was similar in VUS carriers; however, notable variations in γH2AX were observed, and according to combined computational and functional analyses, we reclassified T1001R as VUS-intermediate, T1104P/M1168K and D2819V as VUS (+), and R2027K and G2044A as likely benign. These findings highlight the importance of the variability of VUSs in response to DNA damage before and after Dox-induction and suggest that further investigation is needed to understand the underlying mechanisms.