When your mom told you to eat your broccoli, she may have been giving you good advice on how to avoid cancer.

Researchers already knew that a chemical found in broccoli, cauliflower and related vegetables, called isothiocyanate, appeared to stop the growth of cancer by causing apoptosis, or cell death, in cancer cells. But they didn't know why.

Recent research at Georgetown University found that isothiocyanate sticks to a defective protein found in cancerous cells. The broccoli-born chemical only binds to the protein when it is defective. The normal version is left alone.

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Production of the protein in question is controlled by the gene p53. It normally helps stop a cell from replicating uncontrollably. But when gene p53 is mutated, the protein comes out defective. Not only that, cells with mutated p53 genes are also more resistant to chemical cancer treatments.

P53 mutations occur in half of all human cancers, including lung, breast and colon.

Eating your broccoli may help reduce cancer risks because the presence of isothiocyanate was observed to increase the death rate of cancer cells with the p53 mutation.

Researchers found that after the cauliflower chemical, isothiocyanate, bound to the defective p53 protein, breast cancer cells died. One reason for this may be that the mutated gene also makes the cancerous cells vulnerable to toxic effects from isothiocyanate that normal cells are resistant to.

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Fung-Lung Chung and colleagues at Georgetown University published their findings in the  American Cancer Society's Journal of Medicinal Chemistry.

IMAGE 1: Broccoli (Wikimedia Commons)

IMAGE 2: Cauliflower (Wikimedia Commons)