An experimental breast cancer vaccine makes mice reject tumors — even cancers no longer sensitive to Herceptin. The vaccine targets breast cancers that grow wildly in response to a growth factor called HER-2. About 25% of women with breast cancer have HER-2 positive tumors.
Herceptin, a man-made antibody approved for the treatment of breast cancer, targets these cancers. But after a while, tumor cells often become resistant to Herceptin. The new vaccine elicits immune responses that kill HER-2 positive breast tumors in mice, whether or not they’ve become Herceptin resistant, says Wei-Zen Wei, PhD, professor of immunology at Detroit’s Karmanos Cancer Institute.
“Regardless of whether tumor cells are resistant, if immune cells are properly primed by immunization we can destroy these cells,” Wei tells WebMD.
The vaccine developed by Wei’s team uses DNA that carries the genetic code for a key piece of the HER-2 molecule. After injection of the DNA into the skin, a small electric pulse is administered to help cells take up the DNA and produce the protein that elicits immune responses.
Mice given the vaccine made anti-HER-2 antibodies. The vaccine also primed cellular immune responses that attacked breast cancer tumors. These cellular responses alone were enough to kill HER-2 positive cells in mice unable to make antibodies.
A version of the vaccine is now undergoing human safety tests. … – webmd