An Embryonic Stem Cell–Like Signature Identifies Poorly Differentiated Lung Adenocarcinoma but not Squamous Cell Carcinoma

Abstract

Purpose: An embryonic stem cell (ESC) profile correlates with poorly differentiated breast, bladder, and glioma cancers. In this article, we assess the correlation between the ESC profile and clinical variables in lung cancer. Experimental Design: Microarray gene expression analysis was done using Affymetrix Human Genome U133A on 443 samples of human lung adenocarcinoma and 130 samples of squamous cell carcinoma (SCC). To identify gene set enrichment patterns, we used the Genomica software. Results: Our analysis showed that an increased expression of the ESC gene set and a decreased expression of the Polycomb target gene set identified poorly differentiated lung adenocarcinoma. In addition, this gene expression signature was associated with markers of poor prognosis and worse overall survival in lung adenocarcinoma. However, there was no correlation between this ESC gene signature and any histologic or clinical variable assessed in lung SCC. Conclusions: This work suggests that not all poorly differentiated non–small cell lung cancers exhibit a gene expression profile similar to that of ESC, and that other characteristics may play a more important role in the determination of differentiation and survival in SCC of the lung. (Clin Cancer Res 2009;15(20):6386–90)