MT-ND6 and Carcinoma, Lewis Lung: Further evidence of mtDNA mutations being associated with malignant neoplasms and driving the progression of cancer concerns the ND6 gene, which encodes the core subunit 6 of complex I. The m.G13997A (Pro25Leu) mutation of the ND6 subunit is found in particularly aggressive murine Lewis lung carcinoma cell lines with a high metastatic potential [33,34].