Chemotherapeutic Agents in Brain/Breast

RATIONALE: Drugs used in chemotherapy work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Lapatinib may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Monoclonal antibodies, such as trastuzumab, can block tumor growth in different ways. Some block the ability of tumor cells to grow and spread. Others find tumor cells and help kill them or carry tumor-killing substances to them. Studying samples of tumor tissue and blood from patients may help doctors understand how well these drugs can be carried to the brain. PURPOSE: More definitive knowledge of the penetration of chemotherapeutic and other agents into the brain is necessary for the future rational design of drug and drug regimens that target brain metastases. This clinical trial is studying how well capecitabine, cyclophosphamide, doxorubicin, gemcitabine, lapatinib, paclitaxel, trastuzumab, or vinorelbine penetrates brain tumors.