OTTAWA, Jan. 30 (Xinhua) -- Canadian researchers have found that a certain enzyme that is activated by the gene ERBB2 is related to the development of breast cancer, opening new ways of treating the disease, said the journal Nature Genetics in its online issue for this week.

    Mice lacking the enzyme show resistance to the development of breast cancer tumors, researchers from McGill Cancer Center in Montreal say.

    The enzyme is activated by the gene ERBB2, which is found in about 40 percent of women with breast cancer.

    The researchers worked with mice that usually develop breast cancer because the animals express the gene too strongly.

    The team was able to delay the development of breast tumors using one of two strategies -- deleting an enzyme activated by the gene or giving an inhibitor of the enzyme.

    Removing the enzyme, called protein tyrosine phosphatase 1B or PTP1B, also prevented the cancer from spreading to the lungs.

    A medication, Herceptin, already exists that can deactivate the gene and is used to treat women with certain types of breast cancer.

    The enzyme inhibitor could be tested in combination with Herceptin in clinical trials within one year, the researchers said.