Introduction: The methylation status of selected new p53 target genes in bladder, kidney and testicular cancer was investigated to find similarities in methylation frequency and individual levels of methylation with regard to the histopathological classification and biological behavior.
Material and methods: The patients' samples were evaluated using real-time methylation-specific PCR (MSP) investigating the methylation status of APAF-1, CASP-8, DAPK-1 and IGFBP-3. Included were 103 patients with bladder cancer, 85 patients with kidney cancer and 42 patients with testicular cancer in non-advanced and advanced tumor stages. Non-cancerous tissue from 49 patients was used as control.
Results: Methylation frequency was highest for APAF-1 (88-100%) and DAPK-1 (17-86%) through all the different tumor types. Highest APAF-1 and DAPK-1 levels of methylation were found in the advanced tumor groups. In normal tissue, methylation frequency and methylation levels were significantly lower. APAF-1 methylation was also frequent in normal testicular tissue but to lower methylation levels as in cancerous tissue. APAF-1 and IGFBP-3 methylation levels were significantly higher in recurrent superficial and muscle-invasive bladder tumors. Methylation levels of APAF-1 also correlated with higher risk for recurrent metastatic disease in non-advanced tumors of the kidney.
Conclusions: The methylation profile observed demonstrates a substantial role of the APAF-1 gene in tumorigenesis. The different methylation pattern in testicular cancer might represent a different methylotype of this cancer. The extent of promoter methylation may be a promising target for application as a tumor marker in urogenital cancer disease.
2008 S. Karger AG, Basel.