CLEVELAND — A first-of-its-kind vaccine to prevent breast cancer has shown overwhelmingly favorable results in animal models, according to a study by researchers at Cleveland Clinic’s Lerner Research Institute.
The researchers found that a single vaccination with the antigen -lactalbumin prevents breast cancer tumors from forming in mice, while also inhibiting the growth of already existing tumors.
Enrollment in human trials could begin next year.
If successful, it would be the first vaccine to prevent breast cancer.
“We believe that this vaccine will someday be used to prevent breast cancer in adult women in the same way that vaccines have prevented many childhood diseases,” said Vincent Tuohy, an immunologist in Cleveland Clinic’s Lerner Research Institute.
“If it works in humans the way it works in mice, this will be monumental. We could eliminate breast cancer.”
Mice study.
In the study, genetically cancer-prone mice were vaccinated half with a vaccine containing -lactalbumin and half with a vaccine that did not contain the antigen.
None of the mice vaccinated with -lactalbumin developed breast cancer, while all of the other mice did.
The U.S. Food and Drug Administration has approved two cancer-prevention vaccines, one against cervical cancer and one against liver cancer. However, these vaccines target viruses the human papillomavirus (HPV) and the Hepatitis B virus (HBV), not cancer formation.
Difficult research.
In terms of developing a preventive vaccine, cancer presents a quandary not posed by viruses.
While viruses are recognized as foreign invaders by the immune system, cancer is not. Rather, cancer is an over-development of the body’s own cells. Trying to vaccinate against this cell over-growth would effectively be vaccinating against the recipient’s own body, destroying healthy tissue.
The key, Tuohy said, is to find a target within the tumor that is not typically found in a healthy person.
In the case of breast cancer, Tuohy and his team targeted -lactalbumin a protein that is found in the majority of breast cancers, but is not found in healthy women, except during lactation.
Therefore, the vaccine can rev up a woman’s immune system to target -lactalbumin, thus stopping tumor formation without damaging healthy breast tissue.
Vaccinate after 40.
The strategy would be to vaccinate women over 40 when breast cancer risk begins to increase and pregnancy becomes less likely.
(If a woman would become pregnant after being vaccinated, she would experience breast soreness and would likely have to choose not to breast feed.)
For younger women with a heightened risk of breast cancer, the vaccine may be an option to consider instead of prophylactic mastectomy.
