An update on the diagnostic and prognostic value of MUC4 expression in gastric cancers

INTRODUCTION: MUC4 is overexpressed in gastric cancer and its precursor lesions and plays an essential role in disease progression. AREA COVERED: In this review, we describe the diagnostic and prognostic value of MUC4 expression in gastric cancer. First, we provide a summary of gastric cancer pathogenesis and its intricate relationship with mucin expression. We will then provide an extensive description of MUC4 expression in gastric cancer and its diagnostic and therapeutic significance. EXPERT OPINION: Apart from its protective role in normal physiology, MUC4 contributes to disease progression and metastasis in several malignancies, including gastric cancer. MUC4 is expressed at negligible levels in normal gastric mucosa. However, some patients with intestinal metaplasia and gastric cancer have high levels of MUC4 expression, particularly in the pit cell compartment. The expression of MUC4 in metaplastic pit cells is associated with increased proliferation, inflammation, and epithelial-to-mesenchymal transition. Hence, evaluating MUC4 expression in precursor lesions may help stratify disease and identify cases in which curative surgery should be performed. MUC4 expression in gastric cancer is associated with disease aggressiveness, lymphatic invasion, and nodal metastasis. Due to its role in disease pathobiology, it is a promising target for the diagnosis and therapy of gastric cancer.