Expression profile of cancer-testis genes in transitional cell carcinoma of the bladder

To explore the expression profile of multiple cancer testis (CT) genes in transitional cell carcinoma of bladder (TCC), and investigate its possible correlation with clinicopathologic characteristics.

The mRNA expression of 6 CT genes was detected using reverse transcription polymerase chain reaction (RT-PCR) for 102 TCC samples (59 Ta-T1, 43 T2-T4, 44 G1, 32 G2, and 26 G3 samples) as well as the matching adjacent normal bladder mucosa for each sample. The MAGE-A3 protein expression was also determined by immunoblotting. Immunohistochemistry was performed in selected samples to confirm the MAGE-A3 protein expression.

The mRNA expression of all 6 CT genes was detected with relatively high frequencies in TCC tissues. The percent of samples positive for each gene in the TCC samples are: MAGE-A3, 58.8%; MAGE-A1, 56.9%; cTAGE-1, 52.9%; MAGE-A12, 51%; cTAGE-2, 49%; and NY-ESO-1, 45.1%. Furthermore, MAGE-A3 protein expression was positive in 52.9% of TCC tissues by immunoblotting. Immunohistochemistry showed an exclusively cytoplasmic staining pattern of MAGE-A3 protein. Neither CT gene mRNA expression nor MAGE-A3 protein expression was found in the adjacent normal tissue. There was no significant correlation between CT gene expression and clinicopathologic characteristics (P > 0.05).

All six CT genes are highly expressed in TCC, and may serve as therapeutic targets of specific immunotherapy for TCC, especially in multi-antigen vaccine preparations.