Introduction: The molecular and genetic events that permit tumor metastasis are not well understood. The process whereby tumor cells escape the primary, local tumor, spread to distant sites in the body and find and create conditions conducive to growth in these disparate tissues remains an area of intense investigation. Metastasis of epithelial tumors, such as breast cancer, to the brain is a common problem, with significant consequences with respect to neurological dysfunction and shortening of survival.
Objective: To study two subset of patients with breast cancer metastatic to the brain, to identify genes and proteins that facilitate metastasis, particularly in women who over-express the growth factor receptor HER2, in which an increased risk of brain metastasis has recently been identified.
Study Population: 78 patients with breast cancer metastatic to the brain (39 women whose tumors are HER2-(-) and 39 women whose tumors are HER2-(+)) to compare with published microarray studies of non-metastatic breast cancer patients with these tumor types as well as with one another to help explain the differential trend toward metastasis in patients treated with Herceptin, a new therapy directed at HER-2 over-expressing tumors.
Anticipated Risks and Benefits: Less than minimal risk to the patients to sample tissue already removed from the brain as part of medically-necessary surgery and to sample blood. No direct benefit to the patient is expected.
Outcome Estimate and Potential Meaning for the Field: That this very detailed investigation of the genes and proteins expressed differentially between the non-metastatic and metastatic breast cancers, as well as between HER2-(-) and HER2-(+) subtypes will identify new or previously-unsuspected targets for new therapies to either prevent the development of brain metastasis or to treat these brain metastases more effectively.
