Comparison of gene expression in early- and late-stage paired colorectal carcinomas. Gene expression of mitochondria encoded genes in early-stage adenocarcinomas comprised of stages I and II, and late-stage adenocarcinomas comprised of stages III and IV. Staging of tumors was based on the criteria of the American Joint Committee on Cancer. Gene expression profiles were normalized to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) using RT- quantitative PCR. Gene name abbreviations are as follows: ATP synthase 6 (ATP-6), cytochrome oxidase I (COI), cytochrome b (CYB), 12S/MT-RNR1 12S ribosomal RNA (12S/MT-RNR1), NADH dehydrogenase 1 (ND1), NADH dehydrogenase 6 (ND6)