Expression of fibroblast growth factor 9 is associated with poor prognosis in patients with resected non-small cell lung cancer

Objectives: Fibroblast growth factor (FGF) 9 is a member of the FGF family, which modulates cell proliferation, differentiation, and motility. Recent studies show that the activation of FGF signals including FGF9 is associated with the pathogenesis of several cancers; however, its clinicopathological and biological significance in non-small cell lung cancer (NSCLC) is unclear. The purpose of this study was to clarify the characteristics of NSCLC with FGF9 expression. Materials and Methods: We evaluated the expression of FGF9 in resected NSCLC specimens and corresponding non-tumorous lung tissue samples using cDNA microarray and evaluated its clinicopathological characteristics. Results: Nine out of 90 NSCLC specimens (10%) had "high" FGF9 expression compared with corresponding non-cancerous lung tissues. Histologically, of the 9 NSCLC specimens with high FGF9 expression, 5 were adenocarcinoma, whereas none were squamous cell carcinoma. FGF9 expression was not associated with sex, smoking history, or clinical stage. However, in patients with high and low FGF9 expression, the postoperative recurrence rates were 78% and 24% (p= 0.033), respectively. Overall survival was significantly shorter in patients with high FGF9 expression than in those with low FGF9 expression (p<. 0.001). Conclusion: Our data indicate that FGF9 may be a novel unfavorable prognostic indicator and a candidate therapeutic target of NSCLC.