Forty years ago, women who had abnormal results on a Pap smear often
wound up with a hysterectomy. Doctors removed their uterus because they
had no other way to prevent women from developing cervical cancer,
researcher Susan Love says.
Today, she says, doctors can prevent cervical cancer with a vaccine.
That has led some to ask: Could researchers develop a vaccine against breast cancer?
At first glance, the notion seems impossible.
are typically developed only after researchers have a clear target,
such as a virus or bacteria. Scientists don't even know what causes
most breast cancers.
But researchers do know it's possible for
viruses to cause cancer, says James Gulley, a researcher at the National
Cancer Institute who has worked on vaccines to treat prostate cancer.
causes not only cervical tumors, but cancers of the head and neck, as
well as the vulva, vagina, penis and anus. Hepatitis B can cause liver
cancer, Gulley says. The Epstein-Barr virus can lead to at least three
types of lymphomas.
Another virus, called HMTV, or human mammary
tumor virus, has been found in 40% of breast tumors. HMTV seems
particularly common in a rare but often deadly form of breast cancer,
called inflammatory breast cancer, according to a 2010 study in Cancer.
Scientists don't know if HMTV caused those cancers or was simply along for the ride.
At this point, doctors say they have more questions than answers about the role infections might play in breast cancer.
Breast cancer advocates - tired of seeing women beaten down and burned by toxic treatments - are eager for a game-changer.
not going to get very far unless we ask those big questions," says Fran
Visco, president of the National Breast Cancer Coalition. As a country,
the USA focuses "the vast majority of research dollars on the next
treatment for breast cancer. But we only see incremental benefits from
all of these treatment drugs."
Looking at drugs in the pipeline,
Visco says, "there's nothing on the horizon that could have a major
impact on breast cancer. We don't want to continue to just creep
That's why the National Breast Cancer Coalition has
organized a vaccine initiative called the Artemis Project. Seed grants
will allow researchers to scour breast cancer genomes - the tumors'
entire collection of genes - to look for infectious microbes.
Avon Foundation for Women has committed $6 million to learning whether
infections contribute to breast cancer. Scientists will study 1,000
breast cancer samples whose genomes have been sequenced, looking for
signs of viruses or bacteria.
Doctors from the Cleveland Clinic
are taking a slightly different approach to developing a preventive
vaccine, focusing on a protein expressed on cancer cells, but not
healthy tissue, except during lactation. This research is in some of the
earliest stages, and has been tested only on mice.
scientists are taking a related approach, testing treatment vaccines
designed to prevent tumors from metastasizing, or spreading, to other
organs, a condition that is fatal.
Doctors at the University of
Pennsylvania, for example, are targeting HER2+ breast tumors, whose
cells have lots of copies of a protein called HER2.
testing personalized cancer vaccines, made with women's own immune
cells. Doctors are testing the vaccines in women with DCIS, or ductal
carcinoma in situ, a very early breast cancer or precancer.
vaccinate these women after surgeons have removed their tumors, hoping
the vaccine will prevent their cancers from coming back.
Women will have to wait years to know if their vaccine has worked, because relapses often occur many years after diagnosis.
proteins on cancer cells is difficult, because cancers arise from the
body's own cells, Gulley says. Scientists have to be careful to find a
protein that is found on cancer cells but not healthy cells, to avoid
causing a dangerous autoimmune reaction.
However daunting the task, Love says, scientists need to find more ways to prevent breast cancer.
Angelina Jolie learns she has a breast cancer gene, we don't know what
else to do, so we cut her breasts off," says Love, president of the Dr.
Susan Love Research Foundation. "We have to be looking for the cause. I
worry that we don't, that we're paying too much attention to the
treatment, which comes with a huge cost."