Epigenomics AG of Frankfurt, Germany has been awarded U.S. Patent No. 7,229,759 ("Highly sensitive method for the detection of cytosine methylation patterns," issued June 12, 2007). The '759 patent, covering a method for the detection of cytosine methylation in genomic DNA samples, is the fourteenth U.S. patent to be awarded to the Frankfurt, Germany-based biotech company.
DNA methylation is a naturally occurring means by which cells regulate gene transcription. Methylation occurs when cytosine is modified via the addition of a DNA methyl group. The methyl group subsequently interferes with the binding of transcription factors and allows for chromatin condensation, thereby terminating gene activity. Specific methylation at cytosines throughout the genome results in the specific targeted reduction for gene transcription. Methylation patterns also form genetic fingerprints specific to various disease states, including cancer, that correspond to the regulation of genes important in disease pathogenesis.
The newly issued patent covers Epigenomics' HeavyMethyl® and MethyLight® technology (see below) as well as their proprietary line of DNA methylation biomarkers. Through the use of established real-time quantitative PCR techniques, the technology can differentiate between genomic DNA that is either methylation-modified or unmodified. This technology can be used for the high-throughput methylation detection of cancer biomarkers, thereby providing a clinical diagnostic tool for the early detection of cancer at the genetic level.
The '759 patent issued from U.S. Application No. 10/229,370, which was filed on August 27, 2002, and which claims the benefit of International Application No. PCT/EP02/02572, filed March 8, 2002. Independent claim 1 recites:
1. A method for the detection of cytosine methylation in DNA samples, characterized in that the following steps are conducted:
a genomic DNA sample, which comprises the DNA to be investigated as well as background DNA, is chemically treated in such a way that all unmethylated cytosine bases are converted to uracil, while 5-methylcytosine bases remain unchanged;
the chemically treated DNA sample is amplified with the use of at least 2 primer oligonucleotides, as well as a polymerase and at least one blocking oligonucleotide or PNA oligomer which preferentially binds to a 5'-CG-3' dinucleotide or a 5'-TG-3' dinucleotide or a 5'-CA-3' dinucleotide on the background DNA, whereby the DNA to be investigated is preferentially amplified over the background DNA as the template, and
the amplified products are analyzed and the methylation status in the DNA to be investigated is concluded from the presence of an amplified product and/or from the analysis of the amplified product.
Suresh Pillai, Ph.D., is a molecular biologist and a third-year law student at DePaul University College of Law. Dr. Pillai was a member of MBHB's 2007 class of summer associates, and is currently working as a law clerk at MBHB.
Comments