MUC5B and esophageal squamous cell carcinoma: Mechanistically, the inhibition of NOTCH pathway, a pathway frequently mutated in ESCC, was associated with upregulation of glandular mucins (MUC2, MUC3B, MUC5B, MUC17) and downregulation of squamous keratins.43 In this study, mutations in MUC family genes were significantly associated with poor prognosis.