CINCINNATIResearchers have identified a molecule that may be more accurate than existing biological signposts used to predict which breast cancers will develop into advanced forms of the disease.
Detailed Oct. 24, 2007, in an early online edition of the International Journal of Cancer, the discovery could one day influence therapy decisions and prevent patients from unnecessarily undergoing aggressive cancer treatments.
When diagnosing breast cancer, pathologists currently look for elevated levels of three standard molecules known to make tumors grow in the breast. These moleculesestrogen receptor (ER), progesterone receptor (PR) and HER2are used as biomarkers for diagnosis and individually detect only a fraction of breast cancers.
The problem with these biomarkers is that many of them are present at some level in the normal breast, says Georg Weber, MD, PhD, lead investigator of the new study and associate professor of pharmacy at the University of Cincinnati. In addition, they are surface molecules that support growth so they are not necessarily a good predictor of tumor metastasis.
Weber and his team have identified a molecule, osteopontin-c, that is absent from the normal breast and appears to more accurately predict breast cancer that will become metastatic and spread to distant organs from the original tumor site.
In normal levels, osteopontin is a protein used by the immune system to help cells move and migrate. There are three forms of osteopontina, b and cwhich are formed by splicing, or cutting and pasting, ribonucleic acid (RNA) molecules to make variations of the original gene. Osteopontin-a is the normal form that helps with immune functions. Little is known about osteopontin-b, but if present its levels are very low. Osteopontin-c is the molecule Weber and his team discovered is a good biomarker of breast cancer.
In a two-year evaluation of 178 breast tumors, normal and abnormal tissue sam
|Contact: Jamie Davis Kaun|
University of Cincinnati