High FAK combined with low JWA expression: clinical prognostic and predictive role for adjuvant fluorouracil-leucovorin-oxaliplatin treatment in resectable gastric cancer patients

The multifunctional protein JWA was previously identified as a novel regulator of focal adhesion kinase (FAK/PTK2) in suppressing cancer cell adhesion, invasion and metastasis. JWA is downregulated in gastric cancer (GC) and a prognostic and predictive biomarker for resectable GC. However, the value of FAK combined with JWA for GC patients as a biomarker has not been studied. Here we evaluated the roles of FAK alone and combined with JWA in GC patients treated with surgery alone or combined with adjuvant platinum-based chemotherapy. Two tissue microarrays were constructed of specimens from resected GC (n = 709 in total) for detection of FAK and JWA expression by immunohistochemistry. Correlations between both proteins and clinicopathological features as well as prognostic and predictive values were evaluated. Compared with adjacent non-cancerous tissues, FAK protein levels were remarkably up-regulated in GC lesions (P < 0.001). High FAK alone or combined with low JWA expression significantly correlated with worse overall survival (OS) (both P < 0.001 in two cohorts). Simultaneously, JWA plus FAK expression was a more valuable prognostic biomarker than JWA or FAK alone. Moreover, the patients with high FAK only or combined with low JWA had significant benefit from adjuvant fluorouracil-leucovorin-oxaliplatin (FLO) therapy compared with those with surgery alone (P = 0.003); however, the cases with adjuvant fluorouracil-leucovorin-cisplatin (FLP) therapy did not show these effects. FAK plus JWA may serve as a more prognostic and predictive biomarker for GC than each separately with a potential clinical application.