North American white mitochondrial haplogroups in prostate and renal cancer

Purpose: While the mitochondrion is known to be a key mediator of apoptosis, there has been little inquiry into the inheritance pattern of mitochondria in patients with cancer. We compared the mtDNA haplotype in patients with prostate and renal cancer to that in controls to determine if there is an association between mitochondrial genotype and cancer. Materials and Methods: Haplotyping was performed using polymerase chain reaction/digest identification of key polymorphic sites in the mitochondrial genome. A total of 121 and 221 white men with renal and prostate cancer, respectively, were identified following pathological confirmation of cancer, while 246 white controls were selected randomly from a bank of cadaveric organ donor DNA. Statistical analysis was performed and ORs were calculated. Results: Mitochondrial haplogroup U was a highly significant risk factor for prostate and renal cancer vs controls (16.74% and 20.66% vs 9.35%, Fisher's exact test p = 0.019 and 0.005, respectively). The association remained statistically significant in renal cancer even after Bonferroni adjustment for multiple comparisons. Haplogroup U carried an OR of 1.95 for prostate cancer and an OR of 2.52 for renal cancer. Conclusions: The inheritance of mitochondrial haplogroup U is associated with an approximately 2-fold increased risk of prostate cancer and 2.5-fold increased risk of renal cancer in white North American individuals. Therefore, individuals with this mitochondrial haplotype are in a high risk group. Because mitochondrial haplogroup U is found in 9.35% of the white United States population, there are more than 20 million individuals in this high risk group.