Expression and prognostic value of FOXP1 in esophageal squamous cell carcinoma

Forkhead box protein P1 (FOXP1) has been suggested as a prognostic marker in several malignant tumors. However, the significance of FOXP1 in esophageal squamous cell carcinoma (ESCC) is still unclear. The purpose of this study was to investigate the expression pattern of FOXP1 in normal esophageal tissue and ESCC and to analyze the clinicopathological significance and prognostic value of FOXP1 in ESCC.

FOXP1 was detected by immunohistochemistry using tissue microarrays containing tumor tissues and adjacent normal tissues from 270 ESCC patients with oncological follow-up data.

Normal esophageal tissues predominantly showed an exclusive nuclear FOXP1 (n-FOXP1) expression pattern, and no exclusive cytoplasmic FOXP1 (c-FOXP1) staining was found. In ESCC, the expression rates of exclusive n-FOXP1-positive, exclusive c-FOXP1-positive, both nuclear and cytoplasmic positive and complete negative were 14.4%, 28.9%, 10.4% and 46.3%, respectively. High n-FOXP1 expression was significantly correlated with decreased postoperative recurrence and distant metastasis (P < 0.05). Furthermore, elevated c-FOXP1 expression was significantly associated with regional lymph node metastasis and distant metastasis (P < 0.05). High c-FOXP1 expression had an effect on shorter overall survival (OS) time, but the difference was not statistically significant (P > 0.05). Kaplan-Meier analysis showed that ESCC patients with high n-FOXP1 expression survived significantly longer than patients with low n-FOXP1 expression. Multivariate analysis confirmed that patients with high n-FOXP1 staining exhibit good prognosis and n-FOXP1 was an independent factor for ESCC prognosis.

Our results suggest that FOXP1 plays an essential role in ESCC progression and prognosis and may be a useful biomarker for predicting survival.