Researchers at the John Hopkins Kimmel Cancer Centre have developed a test that may be able to detect cancer cells in its early stages. The highly sensitive examinations used tiny crystals called quantum dots to look for DNA attachments that are usually the first signs of cancer, and could be used to identify those who at risk of developing the disease and also give doctor a better idea of the effectiveness of a particular cancer treatment.

The test, which detects both the appearance and quantity of certain DNA changes, was published in a paper called ‘MS-Qfret: a quantum dot-based method for analysis of DNA methylation’ in the August issue of the journal of Genome Research and the findings were also presented at a conference of the American Association of Cancer Research.

Jeff Tza-Huei Wang, an associate professor at John Hopkins whose lab team worked on the breakthrough said “If it leads to early detection of cancer, this test could have huge clinical implications. Doctors usually have the greatest success in fighting cancer if they can treat it in its early stage.”

Wang and his students spent three years developing the techniques with colleagues, and Stephen B. Baylin, the centre’s deputy director and co-author of the Genome Research study said the test was “a very promising platform” in the detection of cancer in its earliest stages and for predicting which patients are most likely to benefit from particular treatments.

The test was more sensitive and produced results more quickly than current methods and, following more success and more rigorous testing, the method could be rolled out for widespread use within five years.

The test focuses on a biochemical change called DNA methylation, which occurs when a chemical group called methyl attaches itself to cytosine, one of the four building blocks of DNA. When methylation develops at critical gene locations, it can stop the release of proteins that suppress tumors making it is easier for cancer cells to develop and multiply. A person whose DNA has this abnormal gene may have a higher chance of developing cancer. These methylation changes seem to appear before the appearance of genetic mutations which is another precursor to cancer.

The John Hopkins team found a way to detect this DNA methylation and single out the defective DNA strands that have methyl groups attached to them by using the quantum dots. This enabled researchers to discover whether the samples studied contained cancer DNA and how much was present, and the larger the amount the higher the cancer risk.