Prognostic Impact of Phosphorylated Discoidin Domain Receptor-1 in Esophageal Cancer

Background: Esophageal squamous cell carcinoma (ESCC) is common in East Asia and also is often deadly. We sought to determine whether measuring the discoidin domain receptor-1 (DDR1)—both total and phosphorylated proteins—could improve our ability to predict recurrence in ESCC. Materials and Methods: Total DDR1 and phosphorylated DDR1 (pDDR1) were measured using semiquantitative immunohistochemistry in a cohort of 60 patients with ESCC. Association between these immunohistochemical measurements and standard clinical-pathological variables such as patient recurrence-free survival was examined using univariate and multivariate analyses. Results: Six patients (10.0%) had regional recurrence and eight patients (13.3%) had distant recurrence. In univariate analysis, early disease recurrence correlated with intense staining of total DDR1 (P = 0.03) as well as intense staining of pDDR1 (P < 0.001). On multivariate analysis, only regional lymph node metastasis (P = 0.04, HR = 4.20) and intensity of pDDR1 immunohistochemistry (P = 0.03, HR = 4.27) emerged as significant independent prognostic factors for recurrence. Conclusions: This study suggests that immunohistochemical measurements of both the DDR1 protein and pDDR1 can provide prognostic value in ESCC, even when other clinical and pathological factors are also being considered.