New Techniques for Analyzing Molecular Changes in Tissue

A study has shown that combining minimally invasive tissue sampling with ultra-sensitive cell analysis, or microgenomics, provides an easier and less-traumatic way to monitor a patient's responsiveness to drugs. The results were presented at the annual meeting of the American Association of Cancer Research in Phoenix (AZ, USA).

Over time, doctors and researchers may require repeated tissue samples and analysis to monitor the effectiveness of drugs being developed to prevent the growth of breast cancer, for example. In the study, researchers analyzed fine needle aspiration (FNA) tissue samples from 13 high-risk women, using small-gauge needles similar to those used to obtain a blood sample. Then they carefully selected 100-500 of the most abnormal-appearing cells from the thousands of cells in the fine needle aspirate. The atypical cells were selected using laser capture microdissection (LCM), a proprietary approach developed by Arcturus (Mountain View, CA, USA) and the US National Institutes of Health.

With the precision of laser capture, the researchers performed subsequent cell analysis on a population of atypical cells, rather than on the whole specimen. LCM avoids analyzing a mixture of healthy and precancerous cells found in breast cancer, which can distort test results. The FNA samples were preserved in formalin to prevent degradation of the tissue. New extraction techniques developed by Arcturus reverse the cross-linking process caused by the formalin and allow extraction and purification of messenger RNA (mRNA) from the samples, used to measure the expression levels of key genes that may signal premalignant changes.

"These same techniques can be used by the research and diagnostic testing communities to process very small tissue samples that are preserved by the standard method of formalin fixation,” said Mark G. Erlander, Ph.D., co-senior investigator and chief scientific officer of Arcturus. "Gene expression analysis can be performed on the most suitable analysis platform, from microarray technology to PCR.” The new techniques were developed by Arcturus and researchers at the University of Kansas Medical Center (Kansas City, KS, USA).




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