Expression, Function, and Prognostic Value of MAGE-D4 Protein in Esophageal Squamous Cell Carcinoma.

We previously reported that expression of melanoma-associated antigen (MAGE)-D4 mRNA was a prognostic factor for esophageal squamous cell carcinoma (ESCC). The aim of this study was to validate the expression of MAGE-D4 in two additional patient cohorts, and to investigate its biological functions. The role of MAGE-D4 in cell proliferation, adhesion, and migration was determined by gene knockdown experiments in the KYSE590 cell line. MAGE-D4 protein expression was analyzed in ESCC tissues by immunohistochemistry. A second validation cohort consisted of an ESCC mRNA dataset from The Cancer Genome Atlas. Knockdown of MAGE-D4 significantly decreased cell proliferation and migration. Expression of MAGE-D4 protein was significantly associated with disease-free survival. In the second validation cohort, high MAGE-D4 mRNA expression was associated with significantly shorter overall survival and disease-free survival. MAGE-D4 plays an important role in the malignant behavior of ESCC. MAGE-D4 was validated as a prognostic indicator in two independent ESCC patient cohorts.