Cancer stem cells are few in number but key to cancer recurring and spreading, the researchers said.
Researchers at the University of Michigan Comprehensive Cancer Center in Ann Arbor found the compound -- sulforaphane -- prevented new tumors from growing in mice and killed cancer stem cells in the laboratory.
"Sulforaphane has been studied previously for its effects on cancer, but this study shows that its benefit is in inhibiting the breast cancer stem cells," study author Duxin Sun said in a statement. "This new insight suggests the potential of sulforaphane or broccoli extract to prevent or treat cancer by targeting the critical cancer stem cells."
Sun and colleagues took mice with breast cancer and injected varying concentrations of sulforaphane from the broccoli extract. They found a marked decrease in the cancer stem cell population with little effect on the normal cells after treatment with sulforaphane.
The study, published in Clinical Cancer Research, also found cancer cells from mice treated with sulforaphane were unable to generate new tumors. In addition, sulforaphane used on human breast cancer cell cultures in the lab also yielded similar decreases in cancer stem cells.