Expression of focal adhesion kinase and phosphorylated focal adhesion kinase in human gliomas is associated with unfavorable overall survival

Abstract

Human glioma is a malignancy that has no effective systemic therapy. Focal adhesion kinase (FAK) is overexpressed in various invasive and metastatic tumor cells. To investigate its prognostic value in human gliomas, which currently is unknown, we examined the expression patterns of FAK and its activated form, phospho-FAK (FAK pY397), and analyzed the correlation between their expression and prognosis in patients with gliomas. Immunohistochemical staining was performed to detect FAK and phospho-FAK expression patterns in the biopsies from 96 patients with primary gliomas. Kaplan-Meier survival and Cox regression analyses were performed to evaluate the prognosis of patients. As a result, the immunohistochemical analysis revealed that FAK and phospho-FAK both were associated significantly with the Karnofsky performance scale (KPS) score and World Health Organization (WHO) grades of patients with gliomas. Especially, the positive expression rates of FAK and phospho-FAK were significantly higher in patients with a higher grade (P = 0.01 and 0.02, respectively) and a lower KPS score (P = 0.006 and 0.008, respectively). The patients with FAK positive expression correlated with a poor prognosis of human gliomas (P = 0.006) as well as phospho-FAK (P = 0.01). The survival rate of the patients with FAK+/phospho-FAK+ expression was the lowest (P < 0.05), and conjoined expressions of FAK/phospho-FAK were an independent prognostic indicator of human gliomas (P < 0.05). In conclusion, the results suggest that the elevated expression of FAK and phospho-FAK is an important feature of human glioma. A combined detection of FAK/phospho-FAK coexpression may benefit us in the prediction of the prognosis of human glioma.