Mitochondria genes may influence cancer risk.

People with cancers of the kidney or prostate are more likely to have a certain genetic variant in the mitochondria within their cells than are people without these malignancies. The discovery might offer a way to identify people at highest risk of developing these cancers, says John A. Petros of Emory University in Atlanta.

Mitochondria, which are the energy powerhouses in cells, have their own genes. Petros and his colleagues looked at tumor cells from 121 kidney cancer patients and 221 prostate cancer patients and compared their mitochondrial DNA with that of 246 people without cancer. The team found that mitochondria with genetic features designated as haplotype U, which is present in 9 percent of whites in the United States, were about twice as likely to appear in the cancer patients as in the controls.

Petros suspects that the mitochondrial proteins encoded by these variant genes somehow thwart programmed cell death, a cancer-suppressing mechanism.--N.S.