Two genes distinguish lung cancer from normal tissue

The ratio of two genes that are expressed only in normal or neoplastic lung cells is highly sensitive and specific for the identification of tumors, German researchers report in a new study.

Dr. Hans-Stefan Hofmann of the Martin Luther Universitat Halle-Wittenberg in Halle, Germany, with colleagues there and elsewhere, used microarray expression profiling to generate a list of lung or lung-tumor specific target genes. Then, in studies with 99 lung tumor samples and 15 normal tissue samples, they analyzed the possibility that ratios of gene expression levels could be used to discriminate between tumor and normal tissues.In the September 1 issue of the American Journal of Respiratory and Critical Care Medicine, the researchers report that compared to normal lung tissue, in tumor samples, “receptor for advanced glycation end products (RAGE) mRNA is reduced fourfold” and “cyclin-B2 mRNA is upregulated twofold.”When the investigators used the ratio of RAGE per cyclin-B2 in polymerase chain reaction studies of 84 blinded samples, they were able to correctly distinguish non-small cell lung cancer from normal tissue in 94.7%.The technique “allows discrimination of normal and neoplastic lung with a sensitivity of 100% and a specificity of 90.5%,” the authors write. Furthermore, they write, their technique “can be easily adapted and extended to routine clinical application without the need for additional sophisticated analyses.”The authors point out that in other studies, diagnoses obtained by expression-ratio analysis of small amounts of tissue have correlated with response to chemotherapy. Therefore, they believe, their technique has the potential for “broad clinical use in diagnosis as well as in prediction of prognosis in cancer.”(Source: Am J Respir Crit Care Med 2004;170:516-519: Reuters Health News: Oncolink: October 2004.)