"The microarray is fairly new so, right now, researchers are using a lot of different methods and protocols in microarray experiments. That makes it hard for researchers to compare their results to results from other labs,” said Kenneth Olden, Ph.D., Director of the National Institute of Environmental Health Sciences (NIEHS).

"When scientists start using the same methods, equipment and reagents, data can be compared across the entire field of medicine and scientific advances will come more quickly,” he added.

The study, conducted by the Toxicogenomics Research Consortium was initiated in 2001 to asses what causes variation in gene expression experiments within and between labs, as well as within and between microarray platforms.

The researchers systematically examined the processes involved in most microarray or gene expression studies, and found that using a standardised process led to more consistent results. They also found that using commercially manufactured microarrays produced the best results that can be more easily replicated. Using microarrays made in-house by each lab gave less consistent results.

"So far, gene expression data have been very useful in understanding diseases and biological processes,” said Brenda Weis, Ph.D., an author on the study who works at NIEHS. "But if we standardise protocols the knowledge we gain from microarray studies can be used to improve clinical practice. For example, in the Netherlands, microarrays are being used to develop therapies for patients with specific subtypes of breast cancer.”

The study analysed results from seven separate laboratories using two different mouse RNA samples, including a liver RNA and a five-tissue pooled RNA sample, and 12 microarrays, which were either produced commercially or produced in-house by each lab.

MEDICA.de; Source: National Institute of Environmental Health Sciences (NIEHS)