Distinct Mutation Signatures in Peripheral Blood Mitochondrial DNA from Liquid Biopsy Reveal Insights into Pancreatic Cancer

Pancreatic cancer (PC) is a highly aggressive malignancy characterized by limited opportunities for early diagnosis and poor clinical outcomes, underscoring the need for minimally invasive biomarkers to improve detection and patient stratification. Given emerging evidence that mitochondrial DNA (mtDNA) alterations reflect cancer-related biological processes, this study investigated whether blood-derived mtDNA profiles could provide clinically relevant information in PC. In this exploratory study, whole-blood mtDNA from 33 PC patients and 10 healthy individuals were analyzed using next-generation sequencing to assess single-nucleotide variants (SNVs), allele frequencies, and mtDNA copy number. A total of 252 unique mtDNA SNVs were identified, including variants exclusive to PC patients, variants unique to controls, and variants shared between groups. While the overall SNV burden did not differ significantly between groups, PC patients showed distinct mutation distributions and allele frequency patterns, with cancer-exclusive variants occurring predominantly at low allele frequencies. Mutation hotspots were observed in the ND5, COI, and D-loop regions, implicating genes involved in oxidative phosphorylation and mtDNA maintenance. Although mtDNA copy number did not differ significantly between groups, greater variability was observed among PC patients and was associated with differences in survival outcomes. Overall, these findings indicate that blood-based mtDNA profiling captures biologically relevant variation associated with PC and supports further development of integrated mtDNA-based approaches for improved risk assessment and patient stratification.