Collection of CSF Samples From Participants With Metastatic Triple Negative Breast Cancer (TNBC) and HER2+ Breast Cancer With no Prior History Nor Active Radiographically Detectable Brain Metastases

Overview

Background: Breast cancer is the most common cancer among women. It can often spread to the liver, lungs, bones, or brain. Breast cancer that spreads to the brain is often fatal. Researchers want to know if tumor DNA found in spinal fluid, blood, or tumor tissue can help predict when the cancer will spread to the brain. They want to collect these fluid and tissue samples for research. Objective: To collect spinal fluid and other samples from people with breast cancer that has spread to other parts of the body. Eligibility: People aged 18 years and older with HER2-positive or triple negative breast cancer. The cancer must have spread to other parts of the body but not to the brain. Design: Participants will be screened. They will have blood tests to assess kidney function. They will have an imaging scan of the brain. Participants will come to the NIH clinic to have their samples collected: * Spinal fluid. A thin needle will be inserted into the lower back to draw out a sample of fluid from the space around the spinal cord. A physical exam and blood tests will be done to make sure it is safe for participants to have this procedure. * Blood. * Saliva or cheek swabs. They will rub a cotton swab inside of their mouth. * Tumor samples. If participants have had samples of tumor tissue (biopsies) collected in the past, leftover tissue may be used for this study. Participants will be contacted for follow-up every 6 months for 3 years. They may return once a year to provide further samples....

Background * Breast cancer (BC) is the most common cancer among women and the second leading cause of cancer-related deaths in women. * Among the four common metastatic sites of BC - liver, lung, bone, and brain - brain metastases result in the most severe adverse effects and poorest survival outcomes. * Despite robust preclinical data on potential drugs for brain metastasis prevention, designing prevention trials remains challenging due to the difficulty of identifying high-risk populations, the long time required for outcomes to develop, and the associated costs. * Circulating-tumor DNA (ctDNA) from cerebrospinal fluid (CSF) collected from patients who had been locally treated for brain metastases and showed no evidence of metastases on MRI displayed a distinct mutation profile compared to plasma collected at the same time. Primary Objective -To collect CSF samples from participants with metastatic triple negative breast cancer (TNBC) and HER2+ breast cancer (BC) with no prior history nor active radiographically detectable brain metastases Eligibility * Confirmed metastatic HER2+ BC or TNBC * Age \>=18 years Design * This pilot, single-site tissue collection trial aims to collect CSF samples for analysis as potential predictors of brain metastases. * CSF, blood, tumor tissue, and saliva or buccal mucosa will be collected at baseline and optionally during the study. * All participants will be followed up for brain metastasis development every 6 months for up to 3 years.