Cancer-testis gene expression profiling in esophageal squamous cell carcinoma Identification of specific tumor marker and potential targets for immunotherapy

Cancer-testis antigens (CTAs) are often specifically expressed in cancer cells and under normal conditions are only considered to be expressed in the germ line cells and the placenta. CTAs are potential targets for cancer immunotherapy and therefore necessitates their expression profiling. The expression profile of LAGE1, MAGE-A4 and NY-ESO1, their possible correlations and interaction, and the clinicopathological associations of each marker were studied. RNA was extracted from fresh esophagectomy tissues of 41 esophageal squamous cell carcinoma (ESCC) patients prior to any other therapeutic intervention. The relative mRNA expression of LAGE1, MAGE-A4 and NY-ESO1 was assessed with the real-time reverse transcription-polymerase chain reaction (RT-PCR) 5' nuclease assay. The overexpression of LAGE1, MAGE-A4 and NY-ESO1 was found in 39, 90.2 and 41.4% of ESCC samples respectively. Of the patients, 97.5% showed an overexpression of at least one CTA. The relative expression of MAGE-A4 was directly associated with lymph node metastasis and the stage of the tumor (p < 0.05). A significant direct correlation was also detected between the MAGE-A4/LAGE1 and MAGE-A4/NY-ESO1 levels of gene expression. MAGE-A4 is identified as a specific biomarker of ESCC with a possible oncogenic role contributing to tumor progression. Interactions between MAGE-A4, LAGE1 and NY-ESO1 and their significant clinical consequences introduce these CTAs as appropriate targets for a polyvalent cancer vaccine.