Novel tools for unbiased DNA differential methylation screening.

DNA differential methylation screening approaches may be hypothesis driven (preselection of the loci to screen) or unbiased (screening precedes mapping of differentially methylated loci). The latter allow for the identification of sequences demonstrating 'nonclassical' methylation behavior in cancer and, thus, widen our concept of tumor biology. Extensive employment of unbiased screening methods is hampered by the troublesome procedures involved in physically mapping the identified differentially methylated DNA fragments.