Isothiocyanates in cancer prevention.

Area of Science:

• Biochemistry
• Nutritional Science
• Toxicology

Background:

• Isothiocyanates (ITCs) are sulfur-containing compounds in cruciferous vegetables responsible for their flavor.
• In vivo, ITCs conjugate with glutathione, forming dithiocarbamates and mercapturic acids excreted in urine.
• Previous studies suggest inverse associations between ITC intake and cancer risk, particularly lung cancer.

Purpose of the Study:

• To introduce a novel assay for measuring ITCs and dithiocarbamates in biological fluids.
• To validate this assay as an objective biomarker for cruciferous vegetable and ITC intake.
• To explore the relationship between ITC intake, cancer risk, and gene-environment interactions.

Main Methods:

• A quantitative assay using 1,2-benzenedithiol to measure ITCs and dithiocarbamates.
• Measurement of cyclic condensation products in biological fluids.
• Analysis of epidemiological data correlating ITC excretion with cancer risk and GSTM1/GSTT1 genotypes.

Main Results:

• The assay allows for quantitative measurement of ITCs and dithiocarbamates, serving as a reliable biomarker.
• Epidemiological studies show inverse associations between ITC intake/excretion and cancer risk, notably lung cancer.
• A significant gene-environment interaction was observed, with a stronger protective effect in individuals with null GSTM1 or GSTT1 genotypes.

Conclusions:

• This assay provides an objective and accurate method to assess dietary ITC exposure.
• Higher ITC intake is associated with reduced cancer risk, highlighting the potential chemoprotective role of cruciferous vegetables.
• Genetic polymorphisms in GSTM1 and GSTT1 modulate the protective effects of ITCs, warranting further investigation.