Absence of detectable deletions in the mitochondrial genome of human colon tumors.

Changes in structure, function, and gene expression of mitochondria have been demonstrated in colorectal tumors (Wong, J.R.; Chen, L.B. Adv. Cell Biol. 2:263-290; 1988). In this report, mitochondrial DNA from 30 primary human colorectal tumors was compared to that of adjacent histologically normal colonic mucosa and human placenta. No evidence for substantial deletions in the major or minor population of mitochondrial DNA was detected, despite the fact that there are extensive deletions throughout the nuclear genome of such tumors. Hence, alterations in mitochondria in colorectal tumors must be dependent upon other mechanisms.