HMM: A Rare Genetic Mutation Leads to Cancer. The Fix May Already Be in the Drugstore.

When Kelley Oliver Douglass got breast cancer, a genetic counselor posed an odd question: Do you and your children have trouble finding hats that fit?

They did, and that gave the counselor a clue to the source of the cancer: a mutation in a gene called Pten.

In addition to increasing head circumference, this rare mutation markedly raises the risk for several cancers, including prostate and breast cancer (the lifetime risk in carriers is 85 percent), as well as autism and schizophrenia in some individuals.

Ms. Douglass, 51, of Mount Dora, Fla., and her children carry a Pten mutation. Now, researchers have stumbled on a way to counter it — and the treatment may be as close as the local drugstore.

In a study published on Thursday in the journal Science, researchers found evidence that a compound called indole-3-carbinol (i3c) blocks an enzyme that inhibits the activity of Pten. With the gene more active, patients with the mutation may be better protected against cancer.

They could get more i3c simply by eating brussels sprouts, broccoli or other cruciferous vegetables. But to get enough, they’d have to eat a lot: six pounds of brussels sprouts a day — raw.

Yet i3c also is widely available as a dietary supplement, and experts are debating whether to embark on a clinical trial with it.

This is good news that they’re trying very hard to make problematic.