WNK2 and esophageal squamous cell carcinoma: Several groups have mapped genomic alterations in ESCC, and found that the receptor tyrosine kinase (RTK)-mitogen-activated protein kinase (MAPK) pathway is frequently dysregulated; 18.3 and 11.8% of patients with ESCC show overexpression of epidermal growth factor receptor (EGFR) and fibroblast growth factor receptors (FGFR) [8–11].