June 16, 2005
New Gene Chip May Be Early Cancer Diagnosis Tool
A pilot study at the National Institute of Standards and Technology (NIST), in support of the National Cancer Institute's Early Detection Research Network (EDRN), has validated the measurement accuracy of new techniques that use mitochondrial DNA as an early indicator for certain types of cancer. Additional results suggest that a relatively simple diagnostic test using a DNA microarray "chip" could enable early detection of some solid tumors, including lung cancer.
Mitochondrial DNA (mtDNA) plays a role in respiration and the cell's energy conversion mechanism. Since the late 1990s, researchers at the Johns Hopkins University School of Medicine have observed changes in mtDNA sequences in solid cancers, although the nature of the relationship remains uncertain. Their work suggested that particular changes in mtDNA might serve as early indicators for several types of solid cancer. Although promising, this approach is critically dependent on developing reliable, cost-effective, and highly sensitive methods of analysis to detect the cancer indicators against the background of natural variation in mtDNA.The NIST Cancer Biomarker Validation and Reference Laboratory assesses cost, efficiency and reliability of potential diagnostic techniques using biomarkers before further clinical evaluation in other laboratories of the EDRN. The lab found that full mitochondrial genome sequencing using capillary electrophoresis detected mtDNA changes associated with early cancer. In ongoing work, NIST is comparing capillary electrophoresis methods with a newly developed DNA sequencing chip. The mtDNA chips are a promising research tool for early clinical cancer diagnosis that may be faster, easier to interpret, and provide higher throughput than other methods. A paper describing the NCI-NIST work appears in the May issue of the Journal of Molecular Diagnostics.
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