Testing the Use of Fulvestrant and Binimetinib Targeted Treatment for NF1 Mutation in Hormone Receptor-Positive Metastatic Breast Cancer (A ComboMATCH Treatment Trial)

Inclusion Criteria: * Patient must have enrolled onto EAY191 and must have been given a treatment assignment to ComboMATCH to EAY191-N2 based on the presence of an actionable mutation as defined in EAY191 * The patient must be enrolled on the ComboMATCH Master Registration Trial EAY191 * Note: Patients must fulfill all eligibility criteria outlined in the ComboMATCH Registration Trial EAY191 at the time of registration to EAY191-N2. This includes submission of next-generation sequencing (NGS) data from one of the National Cancer Institute (NCI) credentialed designated laboratories for all potential patients prior to treatment trial assignment. Copy number and allele frequency cutoff as per the Registration protocol * Patients must have disease that can be safely biopsied and agree to a pre-treatment biopsy or, if disease cannot be safely biopsied, have archival tissue available from within 12 months prior to the date of registration on the ComboMATCH registration trial (EAY191) * Please note the current actionable marker of interest (aMOI)/actionable alteration list for this treatment trial can be found on the Cancer Trial Support Unit (CTSU) ComboMATCH Registration protocol page * Please note novel/Dynamic aMOI can be submitted for review per the process described in the ComboMATCH Registration protocol * A COMBOMATCH TREATMENT TRIAL EAY191-N2 ELIGIBILITY CRITERIA: * The patient or a legally authorized representative must provide study-specific informed consent prio…