|
Researchers are working on a new saliva test to help detect breast cancer, according to
data presented at the annual meeting of the International Association for Dental Research.
The test measures the amount of HER2 found in a sample of a patient’s saliva. HER2 is
a genetic material that, when present in large amounts, has been associated with breast
cancer. While the new test is still under development, researchers believe that it may
eventually help to detect breast cancer in its early stages and also help physicians
monitor treatment in women already diagnosed with the disease.
HER2 (also written HER2/neu) is a growth factor
found on the surface of cells. When functioning normally, HER2 has been found to be a key
component in regulating cell growth. However, when the HER2 growth factor is altered,
extra HER2 receptors may be produced. This over-expression of HER2 causes increased cell
growth and reproduction, often resulting in more aggressive breast cancer cells. HER2
over-expression affects approximately 25% to 30% of breast cancer patients.
To conduct their research, Dr. Charles F. Streckfus of the University of Mississippi
Medical Center in Jackson, Mississippi and his colleagues performed the saliva test on 125
women. Some of the women had already been diagnosed with breast cancer, others had benign (non-cancerous) breast conditions, and others were
healthy. Dr. Streckfus and his team first attempted to identify the HER2 growth factor in
the women’s saliva and then determine the amount of HER2.
According to research presented at the International Association for Dental Research
meeting in March 2002, Dr. Streckfus and his colleagues were able to link 87% of the
breast cancer cases to high HER2 saliva levels in the women. The researchers also believe
that high levels of HER2 would show up in blood samples from these women.
Dr. Streckfus’ team, who has been studying the HER2 saliva test for five years,
has enrolled 1,100 women to participate in a new clinical trial that will attempt to
confirm their earlier findings. If the trial is successful, the company that makes the
test is expected to file for approval from the U.S. Food and Drug Administration by the
end of 2003, along with another commercial version of the test.
According to Dr. Streckfus, the test is not meant to replace breast cancer screening
tests, such as mammography or physician-performed clinical breast exams. However, if proven beneficial,
the saliva test could be a valuable supplement to these established screening methods, or
it could be used as a follow-up test if a screening mammogram detected a breast
abnormality. In addition to detecting breast cancer, Dr. Streckfus believes that the
saliva test could be used on breast cancer patients to determine whether their treatments
are succeeding.
However, the saliva test would not likely detect breast cancer in all women who had the
disease because the test identifies elevated HER2 protein levels, which occurs in only
around 30% of breast cancer cases. Recently, researchers have developed a drug therapy
called Herceptin (generic name, trastuzumab) that seeks out
and destroys extra copies of HER2. Herceptin is one of the new "targeted" drug
therapies that many experts believe will become more commonly used as advances in cancer
treatment continue.
Guidelines for early breast cancer detection:
- All women between 20 and 39 years of age should practice monthly breast
self-exams and have physician-performed clinical breast exams at least every three
years.
- All women 40 years of age and older should have screening mammograms every one to two
years. Women 40 and older should also practice monthly breast self-exams and have yearly
clinical breast exams. The clinical breast exam should be conducted close to and
preferably before the scheduled mammogram.
- Women 50 years of age and older should have annual screening mammograms, practice
monthly breast self-exams, and receive yearly clinical breast exams.
Additional Resources and References
|
