FAP Expression and Its Association with the Prognosis of Gastric Stromal Tumors

【Abstract】 Objective To determine the association of FAP expression with the prognosis of gastric stromal tumors (GSTs). Methods Paraffin-embedded GSTs samples were collected from January 2010 to December 2013 in the department of pathology of our hospital. FAP expression was examined by immunohistochemistry staining. Its correlations with clinical pathological characteristics and prognosis of GSTs were analyzed. Results A total of 98 cases were included in this study. FAP was expressed in the cytoplasm of GSTs cells, with a positive rate of 42.9%. No FAP expression was found in normal gastric tissues. No differences of FAP expression were found in patients with different gender, age and tumor mitotic counts (P >0.05). Tumor diameter and risk classification were associated with FAP expression (P <0.05). Higher levels of FAP expression were found in larger and higher risk tumors. No significant correlations between FAP expression and routine immunohistochemical markers were found. Log-rank univariate survival analysis showed that mitotic counts, tumor size, postoperative IM and FAP expression were associated with recurrence free survival of GSTs patients with intermediate-high risks (P <0.05). Cox multivariate survival analysis showed that mitotic counts, tumor size, postoperative IM and FAP were independent predictors for the prognosis of GSTs patients with intermediate-high risks (P <0.05). Conclusion FAP is expressed in the cytoplasm of gastric GIST cells, but not in normal gastric tissues. FAP is a predictor for the prognosis of GSTs patients with intermediate-high risks.