Quantum-Dot Based Method Detects Early Signs of Cancer

Using tiny crystals called quantum dots scientists developed a sensitive test to find DNA attachments that frequently are early warning signs of cancer. The test, which detects both the presence and the quantity of DNA changes, could alert people who are at risk of developing the disease and also help monitor certain cancer treatments.

The target of the nanotechnology assay, called mass spectrometry quantum dot fluorescence resonance energy transfer (MS-qFRET), was DNA methylation, which occurred when a methyl group called attached itself to cytosine, one of the four nucleotides of DNA. When methylation occurred at critical gene locations, it halted the release of proteins that suppress tumors, making it easier for cancer cells to form and multiply. The methylation changes also appeared to be an early event that precedes the appearance of genetic mutations, another precursor to cancer.

A study, which included the detection of DNA markers in sputum from lung cancer patients, was designed to show that the nanotechnology was sound. Compared to current methods, the test appeared to be more sensitive and delivered results more quickly. "The technique looks terrific, but it still needs to be tested in many real-world scenarios," Stephen B. Baylin, M.D., deputy director of the Johns Hopkins Kimmel Cancer (Baltimore, MD, USA) and a coauthor of the study said, "Some of these studies are already under way here. If we continue to see exciting progress, this testing method could easily be in wide use within the next five years."

The study was published in the August 2009 edition of the journal Genome Research.

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