Gene expression patterns of paired bronchioloalveolar, carcinoma and benign lung tissue

A variant of adenocarcinoma, bronchioloalveolar carcinoma (BAC), has increa sed in incidence since 1950 and now represents 2-14% of all lung cancers. T here has been concomitant diminution in the proportion of squamous cell car cinoma, the most common form of primary lung cancer. The BAC form of adenoc arcinoma occurs disproportionately in women, has an earlier age of onset th an conventional pulmonary carcinoma, and is not linked to smoking. The incr eased incidence of BAC in both smokers and nonsmokers suggests that BAC may have an environmental etiology other than smoking. To explore this possibi lity, we compared the patterns of gene expression in paired samples of tumo r and normal lung tissue from 3 patients with a pathologic diagnosis of BAC . Characterization of the gene expression patterns of the paired tissue sam ples was performed by oligonucleotide microarray analysis of 12,000 known g enes and expressed sequence tags (ESTs). We identified 12 genes that were u p-regulated greater than or equal to2-fold in all 3 tumors and 6 genes that were down-regulated in all 3 tumors to less than or equal to0.20 times the baseline. These findings suggest that large scale transcriptional profilin g of BAC tumors may disclose a pattern of altered cellular expression in re sponse to genetic changes, diseases, and environmental insult; such transcr iptional profiling may aid in diagnosis and therapy.