GPC1 and breast cancer: The results showed significantly higher GPC-1 expression in tumor-derived exosomes compared to normal and benign breast disease samples, and higher levels of GPC-1(+) exosomes in breast cancer patients than in healthy controls and patients with benign breast disease.444 For CTCs detection, the most effective CTCs test for BRCA is still the FDA-approved CellSearch® method.445 This method is an automated immunomagnetic enrichment method based on the EpCAM, which has a high degree of sensitivity and specificity.