MT-ND6 and neoplasm: In contrast, our previous studies provided convincing evidence that mtDNA with a pathogenic G13997A mutation in the ND6 gene (G13997A mtDNA) controls the malignant transformation of carcinoma cells from a poorly metastatic phenotype into a highly metastatic one [10], although mtDNA does not control tumor development (the transformation of normal cells into tumor cells) [10, 11].