DKK3 and head and neck squamous cell carcinoma: DKK3 is reported as overexpressed in esophageal adenocarcinoma (35), head and neck squamous cell carcinoma (36), and hepatoblastoma (37); whereas studies have reported its downregulated in pancreatic cancer (38), clear cell renal cell carcinoma (39), gastric cancer (40), basal subtype of breast cancer (41), and melanoma (42).