Differential gene expression in human lung adenocarcinomas and squamous cell carcinomas.

PURPOSE: Differential cDNA library screening was performed on 7 human lung adenocarcinomas and 7 human lung squamous cell carcinomas and their corresponding adjacent normal tissues using a human lung cDNA library constructed from the normal bronchoalveolar cells of a 72-year-old male smoker. EXPERIMENTAL DESIGN: Of the 2758 clones that were differentially expressed between normal and tumor tissues in the preliminary cDNA library screening analysis, 1163 clones were confirmed by dot blot, revealing a confirmation rate of >40%. DNA of confirmed clones was sequenced and was subjected to GenBank Blast searches. RNA expression levels were then individually analyzed by semiquantitative reverse transcription-PCR. RESULTS: Ninety-two genes/sequences were differentially expressed in adenocarcinomas and/or squamous cell carcinomas compared with their corresponding normal tissues. Several genes were underexpressed by at least 50% in both tumor types such as c-fos, decorin, alpha-2-macroglobulin, platelet endothelial cell adhesion molecule 1, EGR1, and fibronectin. Ribosomal protein S3 was underexpressed only in squamous cell carcinomas, whereas expression of hepatocyte growth factor activator inhibitor type 2, ubiquitin-conjugating enzyme UBC9, and clone 333E23 on chromosome Xq21.1 were altered only in adenocarcinomas. Several genes discovered recently of which the functions are unknown, such as KIAA0728 and KIAA0425, were also differentially expressed in both adenocarcinomas and squamous cell carcinomas of the lung. CONCLUSIONS: Many of these known and novel genes may be involved in human lung tumorigenesis; therefore, additional characterization is warranted and will be beneficial to the understanding of this deadly disease.

Differential expression of critical cellular genes in human lung adenocarcinomas and squamous cell carcinomas in comparison to normal lung tissues.

The Atlas human cDNA expression array was used to evaluate gene expression profile changes in the genesis of human lung adenocarcinomas and squamous cell carcinomas. Gene expression changes between adenocarcinomas and squamous cell carcinomas were also analyzed. Of the 588 gene targets, 262 genes were expressed in these tissues and, of these, 45 genes were differentially expressed by at least two-fold in tumor tissues compared to corresponding normal tissues. Semiquantitative reverse-transcriptase polymerase chain reaction was used to confirm gene expression changes. Only those genes that reflected changes in >50% of the analyzed tissues were included in the final analysis. Ultimately, 26 genes were evaluated with 14 genes overexpressed and 12 genes underexpressed compared to matching normal lung tissues. Although similar expression changes were detected in adenocarcinomas and squamous cell carcinomas for most of the genes analyzed, some subtype-specific differences were also found. Genes encoding cell cycle regulators, intracellular signal transducers, cell receptor and adhesion molecules, growth factors, oncogenes, and apoptotic effectors were differentially expressed in this study. These gene expression changes may directly contribute to the initiation or progression of human lung cancer or may be secondary effects of the tumorigenesis process. Regardless, many of these differences may be useful in the diagnosis and/or treatment of this deadly disease.