Compounds in broccoli, cauliflower, and watercress
block lung cancer progression.                         
A family of compounds found in cruciferous vegetables, such as
broccoli, cauliflower, and watercress, blocked lung cancer progression
in both animal studies and in tests with human lung cancer cells.

Chemoprevention is regarded as one of the most promising and realistic
approaches in the prevention of human cancer. Among naturally occurring
products, sulfur-containing compounds, especially garlic compounds and
isothiocyanates, represent two important and promising chemopreventive
families because of their potent chemopreventive effects in various in vivo and
in vitro models. In recent years, numerous investigations have shown that
sulfur-containing compounds induce apoptosis in multiple cell lines and
experimental animals. [2]

What is Isothiocyanates?

Isothiocyanates are sulfur-containing compounds which are largely
responsible for the typical flavor of cruciferous vegetables. In animals
including humans they are conjugated with glutathione; the first product of
this reaction is a dithiocarbamate, which can be ultimately metabolized to the
corresponding mercapturic acid, excreted in urine. [1]

What is the benefits of isothiocyanates or veggie diets?

Epidemiological studies on the relationship between cancer risk with
isothiocyanate intake or excretion have shown inverse associations, mainly
with lung cancer. The studies are also consistent in reporting a gene-
environment interaction, with a stronger protective effect in persons null for
the GSTM1 or GSTT1 genotype. [1]

Recent study has shown its benefits on lung cancer.

The study's principal investigator Fung-Lung Chung, Ph.D., say the results,
published in a set of papers in the September 15 issue of Cancer Research,
suggest that these chemicals — put into a veggie pill of sorts — might
some day be used to help current and former smokers ward off development
of lung cancer, the leading cause of cancer death in Americans.

One of the two new studies being reported was the first to test whether
these compounds, derived from naturally occurring isothiocyanates, could
have an impact on the stages of cancer development specifically after
exposure to cancer-causing elements . To test that, the researchers induced
lung tumor development in experimental mice by exposing them to tobacco
carcinogens, and then they fed one group of mice the veggie compounds.
They found that, indeed, use of the chemicals resulted in a reduced
development of benign (harmless) lung tumors to malignant tumors,
compared to mice that did not receive the compound.

The second new study looked at the effect of the same compound on human
lung cancer cells, which were forced to grow quickly (as cancer does) because
of insertion of a gene known to be involved in cell growth and regulation. The
laboratory test showed that the derivative of isothiocyanate significantly
pushed the human lung cells to commit “suicide,” compared to cells that
did not have the gene, suggesting that its use may stop fast growing lung
cancer cells from the outset. This study provides some insight onto “one of
the possible mechanisms of action” by which the compounds may offer
some protection against lung cancer development, the researchers said.

These studies were continuation of a 20-year research effort by Chung and
his team, much of it conducted while Chung was at the Institute for Cancer
Prevention before moving to Georgetown University Medical Center. The body
of research they have established on the connection between cruciferous
vegetables and lung cancer is one of the most detailed available.

The study was funded by a grant from the National Institutes of Health.

[1] Bianchini F and Vainio H Isothiocyanates in cancer prevention. Drug Metab Rev. 2004 Oct;36(3-
4):655-67.[2] Wu X, Kassie F, and  Mersch-Sundermann V, Induction of apoptosis in tumor cells
by naturally occurring sulfur-containing compounds. Mutat Res. 2005 Mar;589(2):81-102. Epub
2005 Jan 4. [3] Laura Cavender, Compounds Found in Veggies Can Block Lung Cancer
Progression in Experimental Studies, Georgetown University Medical Center , Press Release,
September 15, 2005