Mitochondrial mutagenesis and oxidative stress in human prostate cancer

Prostate cancer is the most common cancer diagnosed in men in the United States, but the primary cause and the molecular events leading to prostate carcinogenesis are poorly understood. Using the approach of laser capture microdissection, we revealed extensive somatic mitochondrial DNA (mtDNA) mutations in prostatic neoplastic lesions. Inspection of the lesion associated mutations not only provided new insights into the genetics of prostate cancer, but also revealed new patterns of mtDNA mutation in prostate carcinogenesis. Further analysis on a high frequency of multiple mutational events observed in the same neoplastic lesion revealed an unusually rapid process in mitochondrial mutagenesis, suggesting a new process of mitochondrial hyper-mutagenesis in cancer cells, likely mediated by cellular oxidative stress. Thus, active mitochondrial mutagenesis in prostate cancer suggests a prominent role of increased cellular oxidative stress in neoplastic transformation and the increased susceptibility of neoplastic cells to oxidative damage.