Trial Information

Analysis of Brain Metastasis in Patients With Breast Cancer, With and Without Over-Expression of HER-2

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.