Expression of mage genes in transitional‐cell carcinomas of the urinary bladder

Abstract

Human genes MAGE‐1 and MAGE‐3 code for distinct antigens, which are recognized on melanoma cells by autologous cytolytic T lymphocytes (CTL). These antigens may constitute useful targets for anti‐cancer immunotherapy, since no expression of MAGE genes has been observed in normal tissues other than testis. Out of 57 samples of primary transitional‐cell carcinomas of the bladder, 12 (21%) expressed MAGE‐1 and 20 (35%) expressed MAGE‐3. All but one of the tumors expressing MAGE‐1 also expressed MAGE‐3. Genes MAGE‐2 and MAGE‐4, which are closely related to MAGE‐1 and MAGE‐3, were expressed by 30% and 33% of the tumors respectively. MAGE expression was more frequent in advanced tumor stages: 61% of the invasive tumors (stage ± T2) were positive for expression of at least one of the four genes, whereas only 28% of the superficial tumors (stages Ta and Tl) expressed these genes.