Abstract ED03-01: Validation and quantitation of DNA methylation changes

Abstract

Abstract Advances in the molecular mechanisms underlying prostate cancer demonstrates that prostate cancer cells carry a myriad of genomic defects including both genetic and epigenetic alterations such as DNA methylation. Underlying this aberrant DNA methylation is the accumulating body of data hinting that normal prostate cells may be subjected to a relentless barrage of genome-damaging stresses due to both exogenous and endogenous carcinogens, with damage accumulating over time and age. There are increasing numbers of genes that show aberrant DNA methylation changes in human prostate cancer. In addition, recent reports indicate widespread methylation changes that correlate with a broad range of clinical behavior in prostate cancer patients. Thus aberrant DNA methylation changes may represent the integration of environmental or lifestyle exposures and genetic predisposition to prostate cancer. Such events may differ between individuals belonging the same ethnic group or individuals belonging to different ethnic groups. We hypothesize that differential methylation patterns maybe associated with ethnicity and could potentially contribute to the incidence and mortality of prostate cancer. Our research studies validate and quantify selected regions of genes from a genome-wide methylation analysis in a large sample number from African American and Caucasian male patients with prostate cancer. Our preferred method for studying DNA methylation is pyrosequencing over other methods of methylation analysis in that it is processive and quantitative. The principle of pyrosequencing is the real-time detection of pyro-phosphate (PPi), released after each incorporation of a specific nucleotide, initiated by simple primer extension on a PCR product template. Pyrosequencing has both qualitative and quantitative applications, and is optimal for allele quantification, DNA methylation estimation, and for regions that contain multiple polymorphisms (SNPs, IN/DELs) adjacent or in close proximity. Using this approach, we have observed significant differences in the methylation pattern for several genes in prostate tissue samples from African American and Caucasian men. Such alterations can contribute to the biological differences underlying prostate cancer disparity. Citation Information: Cancer Epidemiol Biomarkers Prev 2011;20(10 Suppl):ED03-01.