The primary objective is to describe on an exploratory basis the association between the type of proteomic profile from cerebrospinal fluid (CSF) microvesicles (from unsupervised bioinformatics analysis) and CSF cytology analysis (positive, negative, equivocal) in breast cancer patients with suspected leptomeningeal metastases, on initial CSF samples (hereafter referred to as initial proteomic profile and initial cytology).
