The expression of 349 miRNAs was aberrant in BRCA1-KO fibroblasts following treatment with cancer EVs, of which 169 miRNAs were down expressed and 180 miRNAs were over-expressed in cancer EVs-exposed BRCA1-KO fibroblasts (Fig. 7c and Additional file 1: Figure S6B). Here, BRCA1 is linked to cancer.