MT-ND4 and cancer: Aiming to understand the basis of these differences, we tested the possible differences in correlation for ND1 vs. ND4 between carcinoma and hyperplasia samples, and we found that, despite the small sample size, there was a positive correlation in PBMCs between ND1 and ND4 in hyperplasia samples which was absent in carcinoma samples, and the differences between the two were significant, further stressing that the observed changes in ND4 content were of pathological relevance and restricted to cancer patients.