RAB27A and breast cancer: To explore the effect of breast cancer (BC)-derived sEVs on adipose tissue, we xenografted engineered mouse triple-negative BC (TNBC) cell line 4T1 (4T1/Ctrl) and exosomes secretion impaired 4T1 cells (4T1/Rab27a KO) and those cells were stably expressing a membrane-targeted Lck-GFP (Fig. 1a).