Tumors that have desmoplastic reaction and, therefore, a high content of FAP-expressing CAFs, include gastro-intestinal adenocarcinoma, pancreatic ductal adenocarcinoma (PDAC), cholangiocarcinoma, esophageal, head and neck cancer, thyroid, cancer of unknown primary (CUP), lung, peritoneal, bladder, ovarian and breast cancers. The gene discussed is FAP; the disease is breast cancer.