PITX2 and esophageal squamous cell carcinoma: The expression of paired-like homeodomain transcription factor 2 (PITX2), a downstream effector of Wnt/β-catenin signaling, was observed more frequently in chemoradiotherapy (CRT) resistant ESCC patients than that in CRT effective group (p < 0.05) and was associated with poor disease-specific survival (p < 0.05).