As hypothesized, BRCA1-KO fibroblasts and HEK293 cells showed an uptake of cancer exosomes 3 to 13 times higher (6.6 +/− 0.6 times for BRCA1-KO fibroblasts and 7.7 +/− 2.0 for HEK293 cells) than that measured in control wild type fibroblasts. The gene discussed is BRCA1; the disease is cancer.