Genes affect chemo reaction, study shows

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http://www.cnn.com/2004/HEALTH/conditions/06/08/cancer.genes.ap/index.html

.... Genetic differences among cancer patients may help explain why some

become terribly sick during their treatment and others find chemotherapy a

relative breeze...

.... Many normal genes are found in slightly variant forms. The Mayo team

looked at a gene called DPYD and found that people with two variations were

significantly less likely than those with the usual form to suffer fatigue.

In addition, those with a bit of genetic code called TSER near another

folate gene known as TYMS were more likely to report a positive outlook

while on chemotherapy.

" We believe we have found evidence of a relationship between the genetic

makeup of cancer patients and their quality of life, even before treatment

begins, " Sloan said.

Another study, conducted by Dr. Suk of Massachusetts General

Hospital, identified a genetic variation that seems to influence whether

people treated for advanced non-small cell lung cancer experience vomiting

and other severe gastrointestinal side effects while on chemotherapy.

Her team looked for variations in a gene involved in DNA repair in 147

patients. They found that 30 percent of those with unusual forms of this

gene were likely to have particularly bad side effects, compared with just

14 percent who had the standard gene.

The researchers speculate that people with the variant form of this gene,

called ERCC1, do a worse job of repairing damage caused by the chemotherapy,

and this explains their severe side effects....