ESR1 and neoplasm: In another study that included 13 tumor samples from Israeli patients with metastatic, ER-positive breast cancer who failed multiple treatments, Merenbakh-Lamin and coworkers performed commercially available genetic analysis by next-generation sequencing of 182 cancer-related genes on DNA extracted from formalin-fixed paraffin-embedded tissue samples and reported ER D538G mutation in five patients (38%) [31].