Expression of MAGE‐B Genes in Esophageal Squamous Cell Carcinoma

The MAGE‐B (MAGE‐B1, ‐B2, ‐B3, and ‐B4) genes share strong homology with the MAGE‐A gene family. MAGE‐B1 and ‐B2 encode common tumor‐specific peptide antigens. There is, however, still very little information about the expression of these genes in human gastro‐intestinal carcinomas. We investigated the expression of MAGE‐B1 and ‐B2 genes in 29 cell lines and 53 clinical tumor samples of esophageal squamous cell carcinoma by reverse transcription polymerase chain reaction (RT‐PCR). MAGE‐B1 and ‐B2 gene transcripts were detected by RT‐PCR in 1 (3%) and 6 (21%) cell lines, and in 9 (17%) and 17 (32%) clinical samples, respectively. Among them, 7/29 (24%) cell lines and 19/53 (36%) clinical samples expressed at least either MAGE‐B1 or ‐B2. A significant correlation was found between negative MAGE‐B gene expression and vascular invasion (P=0.008). In 45 out of 53 esophageal carcinoma RNA samples, the MAGE‐A1, ‐A2, and ‐A3 genes were detected in 27 (60%), 23 (51%), and 30 (67%) samples, respectively, while the MAGE‐B genes were detected in 18 (40%) samples. The frequency of MAGE‐B gene expression in esophageal carcinoma was relatively higher than that observed for gastric or colorectal carcinomas (12% and 2%, respectively). Therefore, the MAGE‐B genes could be used as targets in specific immunotherapy of esophageal squamous cell carcinomas.