Supernatants from HEK293 cells transfected with plasmids with human Pn 1-Halotag and 4T1 mouse triple-negative breast cancer (TNBC) cell line, which highly expressed all mPn-ASVs, were used as the positive control, while organs from Pn knockout mice (Pn KO) were used as the negative control. Here, POSTN is linked to triple-negative breast carcinoma.