Breast cancer vaccine kills tumors in mice

DETROIT, Sept. 15 (UPI) -- Wayne State University researchers say a breast cancer vaccine completely eliminated HER2-positive tumors in mice -- without any toxicity.

The study, published in the journal Cancer Research, suggests the vaccine could treat women with HER2-positive, treatment-resistant cancer or help prevent cancer recurrence. The researchers also say it might potentially be used in cancer-free women to prevent initial development of these tumors.

HER2 receptors promote normal cell growth, and are found in low amounts on normal breast cells. But HER2-positive breast cells can contain many more receptors than is typical, promoting a particularly aggressive type of tumor that affects 20 percent to 30 percent of all breast cancer patients, the study says.

Therapies such as trastuzumab and lapatinib, designed to latch on to these receptors and destroy them, are a mainstay of treatment for this cancer, but a significant proportion of patients develop a resistance to them or cancer metastasis that is hard to treat.

"The immune response against HER2-positive receptors we saw in this study is powerful, and works even in tumors that are resistant to current therapies," lead investigator Wei-Zen Wei says in a statement.

"The vaccine could potentially eliminate the need to even use these therapies."