MT-CO1 and colorectal carcinoma: Unexpectedly, when we examined patient-matched colorectal carcinomas we found that, on average, tumor cells displayed an approximately three-fold lower random mutation frequency compared to normal colonic tissue (1.4±0.4×10−5, P = 0.004 for 12S rRNA, 4.1±1.2×10−5, P<0.001 for COXI, 2 tailed paired t-test) (Figure 1A–1B).