The Cutting Edge of Breast Cancer Research
Miryam Z. Wahrman, Ph.D.
Breast cancer research has achieved particular urgency for the Jewish community since the discovery that specific alterations in breast cancer genes BRCA 1 and BRCA 2 are found in significantly higher proportion in the Ashkenazi Jewish population. For instance, according to the National Cancer Institute, up to two percent of Ashkenazi Jews carry three specific mutations in BRCA 1 and BRCA2 that are associated with breast cancer.
In the United States, there are more than 225,000 new cases of breast cancer diagnosed each year. "A new diagnosis every three minutes," stated Barbara Brenner, at a recent dinner of ABCs - After Breast Cancer Surgery, a rehabilitation and counseling organization in New Jersey. Brenner serves as Executive Director of Breast Cancer Action (BCA), a San Francisco based advocacy group. Brenner reported that breast cancer is the leading cause of death in women ages 35 - 55. "We believe there is a link between the environment and breast cancer," states a BCA flier. According to Brenner, the group, which receives 60% of its funding from individual contributions - and "no money from anyone profiting from cancer or the environment", has an annual budget of over half a million dollars. According to their Mission Statement, "We are not afraid to examine all sides of all issues... We cannot be bought... We tell the truth about what we discover... We recognize that structural changes in society are needed to accomplish our mission."
Brenner voiced particular concern over the fact that for more than 70% of breast cancer cases, "we have no idea of the cause." Brenner emphasized that, "the only known cause is radiation."
"While many other environmental links to breast cancer are suspected, concrete proof has not been established," explains a BCA flier. "The complex environment in which we live makes it difficult to prove a cause-and-effect relationship to breast cancer. Despite lack of scientific proof, we can and should reduce our exposures to substances we believe cause cancer..."
"Companies must be made accountable for the products they make," continues the flier. "Rather than assuming that a chemical is harmless, companies... should be required to prove that they are safe."
Brenner explained that Astra Zeneca, the company which produces tamoxifen (a drug used by some breast cancer patients), also sponsors Breast Cancer Awareness Month. Brenner maintains that Astra Zeneca is controlling information regarding breast cancer, and this represents a conflict of interest. She is particularly concerned that much cancer research is industry supported, therefore "it is almost impossible to find a breast cancer researcher without a conflict of interest." Brenner proposes restructuring the research community by setting up a coordinated breast cancer research strategy. "Distribute resources to... people thinking outside the box," offered Brenner. "Cut academic and corporate ties..."
Dr. Teresa Gilewski, a medical oncologist from Memorial Sloan-Kettering Cancer Center, presented an update on the latest research into treatments and cures for breast cancer. Current treatments include the traditional: surgery, radiation, chemotherapy and hormone therapy. New investigations are exploring immunotherapy - including a possible cancer vaccine - which mobilizes the body's own immune defenses to seek out and destroy cancer cells. Immunotherapy is hard to develop, explained Gilewski, since "the immune system is very complicated. It is hard to measure what goes on in the normal immune system."
Development of an effective tumor vaccine has been elusive, since tumors are "heterogeneous", or made up of complex mixtures of different types of cells. So it is necessary to stimulate the immune system to recognize a variety of antigens, or markers on different types of cells. In addition, tumor cells are constantly changing - and eluding the immune system. Finally, the antigens, or markers found on the surface of tumor cells, are also frequently found on normal cells. The immune system develops tolerance for the normal cells of the body, so it may be less likely to seek out and destroy tumor cells which appear normal.
Nevertheless, some tumor markers are unique and can be used to stimulate a reaction. "The immune system must recognize [tumor] antigens as something bad." explained Gilewski. The Sloan-Kettering project involves synthesizing pieces of the antigen to use as a vaccine. The tumor antigen is mixed with KLH, a shellfish protein, or QS21, a substance from tree bark, both of which appear to help stimulate the immune response. Patients who are offered this experimental therapy must have no allergies to seafood, no autoimmune disorders and not be currently receiving chemotherapy, radiation or herceptin treatments.
According to Gilewski, the vaccine trials have shown "that the majority of patients do make antibodies and in many patients the antibodies bind to tumor cells." But not all patients have that response. "So we're constantly working on the vaccines to try to improve that," Gilewski said.
So far there have been 160 women participating in five major breast cancer vaccine trials. Future studies include the testing of a combination vaccine: six antigens will be mixed into one vaccine. "We think that will work better," reasoned Gilewski. "Because... not all the tumor cells in any individual person are going to be the same. So some tumor cells may have one antigen, another tumor cell may have another antigen. So if you can get the immune system to react to multiple antigens you have a better chance of trying to destroy the tumor cells."
"Many people ask, 'how well does the vaccine work?', and we don't know that yet," admitted Gilewski. "Because all of the trials we've done so far have been looking at immune response: 'do we stimulate the immune system?'" She indicated that it will take another year or two to determine whether the vaccine delays or prevents the recurrence of breast cancer.
Currently there are other researchers working on different kinds of vaccines as well. For instance, "they take out immune cells from a person's body, they alter them, and they give them back to [the patient] in a vaccine," reported Gilewski. "So there are many, many ways of stimulating the immune system, and we don't know which one is the best. It's all investigational."
"Many people say 'will there be a vaccine one day that will prevent breast cancer?'" pondered Gilewski. "I don't think it's going to happen any time in the near future because right now we're working on some of the basics... I think there clearly is promise for an immunotherapy type of approach, meaning vaccines, antibodies, for the future."
ABCs can be reached at the Bergen County Y- JCC, phone: (201) 666-6610 ext. 300.
Breast Cancer Action can be contacted at (415) 243-9301 or toll free at 877-2STOPBC. It is found on the web at www.bcaction.org
© 2000 Miryam Z. Wahrman