To determine if NEAT1 is functionally required for the in vivo tumorigenicity of BRCA1-deficienct breast tumor cells, we isolated primary tumor cells from Brca1-deficient mammary tumors developed in MMTV-Cre;Brca1Co/Co mice and established stable Neat1 knockdown in primary Brca1 mutant mammary tumor cell cultures as described in Supplementary Figure S6. Here, NEAT1 is linked to neoplasm.