FOXL1 overexpression is associated with poor outcome in patients with glioma.

Gliomas are the most common primary tumors in adult central nervous system and result in disappointing survival outcomes. FOXL1, as a transcription factor, plays an important role in regulating the expression of genes involved in cell metabolism, proliferation and differentiation. In this study, we investigated the relationship between FOXL1 expression and prognosis of patients with glioma. We selected 611 glioma patients from The Cancer Genome Atlas (TCGA) database and 132 glioma patients from Huai'an First People's Hospital (PFHH). The prognostic values of FOXL1 in glioma were analyzed in both cohorts. In TCGA cohort, the median (10.2389) was used as the cut-off value of FOXL1 mRNA levels in tumor tissue. Kaplan-Meier analysis showed that higher WHO glioma grade (P<0.001) and expression of FOXL1 (P<0.001) were associated with worse overall survival (OS). The univariate Cox regression model revealed that age (P<0.001), WHO grade (P<0.001), histological type (P<0.001) and FOXL1 expression (P<0.001) were associated with prognosis of glioma patients. In PFHH cohort, expression of FOXL1 in tumor cells was detected by immunohistochemistry (IHC) staining based on a tissue microarray (TMA) sample. Kaplan-Meier analysis also showed that WHO glioma grade (P<0.001) and expression of FOXL1 (P=0.012) were associated with OS in glioma patients. The univariate Cox regression showed that WHO grade (P=0.001), histological type (P<0.001) and FOXL1 expression (P=0.013) were associated with prognosis of glioma patients. In both cohorts Kaplan-Meier subgroup analyses showed FOXL expression correlated with OS in high WHO grade subgroup, while low grade subgroup showed no such correlation. This study showed that higher expression of FOXL1 is associated with poor OS of glioma patients in TCGA and PFHH cohorts. Especially, FOXL1 overexpression is associated with worse outcomes in high WHO grade subgroup. Our findings suggest that FOXL1 expression is a candidate predictor of clinical outcome in glioma patients and may act as an effective molecular marker for immunotherapeutic strategies of glioma patients in clinical practice.