Fascin is a circulating tumor marker for head and neck cancer as determined by a proteomic analysis of interstitial fluid from the tumor microenvironment

Background: Head and neck cancer (HNC) is a prevalent cancer worldwide; however, clinically useful tumor markers for HNC have not been identified. Here, we aimed to identify secretory proteins from the tumor microenvironment as candidate circulating tumor markers. Methods: Samples derived from seven pairs of tumor interstitial fluid (TIF) and normal interstitial fluid (NIF) samples from patients with HNC were analyzed. The proteomes were determined by gel-based-mass-spectrometry proteomic methods. The most up-regulated protein, fascin was confirmed in the cancer tissues and cell culture supernatant by immunoblotting and immunohistochemistry assays. Serum fascin was determined in 40 HNC and 40 normal individuals by ELISA. Results: After proteomics analysis, 189 peptides were identified, corresponding to 75 proteins. Of the 21 proteins which were identified more than twice, five up-regulated proteins identified most frequently including fascin. The most elevated fascin was over-expressed in cancer tissues and cell culture supernatant. Serum fascin was significantly up-regulated in the cancer patients (p<0.001) and correlated with pathological lymph node metastasis (p=0.022). To assess the diagnostic efficacy, serum levels of fascin and another potential biomarker SCCA were determined. Fascin showed a high predictable value with an area under the curve (AUC) of 0.808 (95% CI 0.723-0.901) in the receiver operator curve (ROC), compared to 0.501 (95% CI 0.378-0.634) for SCCA. Conclusions: We have identified 75 potential circulating tumor markers associated with HNC, including fascin. Serum fascin could discriminate cancer patients from healthy individuals; thus, it may serve as a circulating biomarker for HNC.