Clinical Findings on Fibroblast Activation Protein in Patients with Gastric Cancer

Human fibroblast activation protein (FAP) is a 97-kDa surface glycoprotein expressed in tumor-associated fibroblasts. In this study, we immunohistochemically examined FAP levels in surgically resected gastric carcinomas and explored their association with clini-copathological findings and prognosis. Sections of paraffin-embedded specimens were obtained from 100 patients with advanced gastric cancer between 1989 and 2001 at our institution, and they were stained with an anti-FAP antibody. Expression of FAP was detected in 64 patients (64%). Lymphatic vessel invasion was observed in 90% of FAP-positive patients (P = 0.015). Blood vessel invasion was observed in 98% of FAP-positive patients (P < 0.001). The disease-specific 5-year survival rate of in the 64 patients with FAP-positive tumors (22%) was significantly lower than in the 36 patients with FAP-negative tumors (34%, P = 0.036). This indicates that vessel invasion is connected with the expression of FAP and that a positive finding of FAP confer a worse prognosis in the patients with gastric cancer.