Numerous scientific studies have shown the cancer protective effects of increasing intake of cruciferous vegetables, including broccoli, cauliflower, Brussels sprouts, kale and cabbage. Among the beneficial chemical components of these vegetables is sulforaphane, a naturally occurring compound that suppresses both cancer cell growth and the growth of new tumor blood vessels (angiogenesis). The antiangiogenic properties of sulforaphane have been studied, and it downregulates the production by cancer cells of key angiogenesis-promoting factors, including vascular endothelial growth factor (VEGF), HIF-1α, matrix metalloproteinase-2 and matrix metalloproteinase-9.

Using an extract of sulforaphane, a group of researchers led by Yanyan Li and Duxin Sun at the Department of Pharmaceutical Sciences, University of Michigan, were able to inhibit the growth of breast cancer stem cells both in laboratory cultures and in mice. A growing body of research indicates that many types of cancer, including breast cancer, are initiated and maintained by a small fraction of tumor stem cells—characteristics that make them an attractive target for therapy.

Reporting their findings in the journal Clinical Cancer Research, the scientists found that sulforaphane reduced the size breast cancers in mice by more than 50%. Further, sulforaphane was able to reduce the numbers of breast cancer stem cells by 65-80% in mice implanted with human breast tumors. These findings provide rationale for future clinical evaluation of sulforaphane for breast cancer chemoprevention, and as an antiangiogenic intervention.