To this end, we sequenced the ND1, ND2, ND3, ND4L, ND4, ND5 and ND6 genes in the tissues of 45 primary tumours (1 case with distant metastasis and 44 distant metastasis-free cases) and 37 brain metastases of NSCLCs and in the tissues of 22 primary tumours (7 cases with distant metastasis and 15 distant metastasis-free cases) and 11 distant metastases of colon cancers, including two matched primary and metastasis samples (Supplementary Tables S1 and S3). The gene discussed is MT-ND4; the disease is neoplasm.