FAP and breast cancer: The results showed that the expression levels of POSTN and FAP in breast cancer (BRCA), lung adenocarcinoma (LUAD), lung squamous cell carcinoma (LUSC), and digestive system tumours such as colon adenocarcinoma (COAD) and oesophageal cancer (ESCA) were significantly higher than those in normal tissues (p<0.001) (Supplementary Fig. 12A-B).