Investigation of tumor-derived extracellular DNA in blood of cancer patients by methylation-specific PCR.

The frequency of APC, RASSF1A, RARbeta, CDH1 and CDH13 gene promoter methylation in samples of DNA isolated from breast and lung patient plasma was studied in order to develop the noninvasive tumor-specific DNA detection method. Methylation of at least one of genes was detected in extracellular DNA from most of the cancer blood specimens. The results obtained indicate that promoter hypermethylation of a number of marker genes represents a promising serum marker for early breast and lung cancer detection.