PRKN and esophageal squamous cell carcinoma: Based on 223 ESCC patients sample analysis by IHC (immunohistochemistry), we found that low PARK2 expression correlated with late tumor stage (P < 0.001), poor differentiation (P < 0.04) (Figure 1D), lymph node (P < 0.001) and distant metastasis (P = 0.0087) (Table 1).