NRBP1 and breast cancer: Utilizing diverse functional assays, both in vitro and in vivo, coupled with a BioID/MS screen, we demonstrate that NRBP1 plays a positive role in TNBC growth and metastasis and determine that this is mediated via a novel pathway involving NRBP1 and the Rac1 GEF P-Rex1, itself a known breast cancer oncogene [18].