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.