DNA methylation is used in most living systems to control gene expression or genetic programs. In mammals DNA methylation occurs mainly at CpG dinucleotides but can also be found at CpA, CpT and CpC sites. Non-CpG methylation is restricted to specific cell types including pluripotent stem cells, oocytes, neurons and glial cells. DNA methylation can function to regulate gene expression and influence the structure of chromatin. Chromatin is the combination of DNA and proteins that make up chromosomes. The spatial organization of chromatin impacts on gene expression, DNA replication and cell mitosis. The epigenetic state of the cell, the tissue of origin and diseased states are linked to specific DNA methylation patterns.
Cancer cells undergo epigenetic reprogramming of their genomes creating a distinct methylation landscape where DNA methylation is clustered at regulatory domains and large tracks of hypomethylated regions in between genes. In 2018 Matt Trau and his team of researchers at University of Queensland, Australia, demonstrated how the cancer-associated methylation landscape, which the team termed Methylscape, can be used as biomarker for cancer diagnosis. Trau showed that Methylscape differences result in differences in purified genomic DNA between cancer and normal cells in the way the DNA aggregates in aqueous solutions. These differences can be detected by differenced in adsoption onto gold nanoparticles using electrochemical and colorimetric techniques. The technology can be used noninvasively on blood because circulating free DNA, released into the blood from cancer or healthy cells. The Methylscape biomarker is universal to most cancer types. The technology cannot determine the cancer type or stage of disease. For further development and licensing of the technology, the research team partnered with the commercialization company UniQuest.