Expression of fibroblast activation protein in human pancreatic adenocarcinoma and its clinicopathological significance

Abstract

To examine fibroblast activation protein (FAP) expression in pancreatic ductal adenocarcinoma (PDAC) and to analyze its relationship with the clinicopathology of PDAC. FAP expression was examined in 134 PDAC specimens by immunohistochemistry, and in four pancreatic cancer cell lines (SW1990, Miapaca-2, AsPC-1 and BxPC-3) by Western blotting assay. We also analyzed the association between FAP expression in PDAC cells and the clinicopathology of PDAC patients. The results showed that the FAP was ex-pressed in both stromal fibroblast cells (98/134, 73.1%) and carcinoma cells (102/134, 76.1%). All 4 pancreatic cancer cell lines expressed FAP protein at different levels. Protein bands corresponding to the proteolytically active 170-kDa seprase dimer and its 88-kDa seprase subunit were identified. Higher FAP expression in carcinoma cells was associated with tumor size (P < 0.001), fibrotic focus (P = 0.003), perineural invasion (P = 0.009) and worse clinical outcome (P = 0.0085). FAP is highly expressed in carcinoma cells and fibroblasts in PDAC tissues, and its expression is associated with desmoplasia and worse prognosis.