Affymetrix SNP array data for 47 lung squamous cell carcinoma and 40 esophageal squamous cell carcinoma samples.

Lineage-survival oncogenes are targeted by gene amplification in cancers arising from the tissues where these genes play a role in normal development. Here we show that the transcription factor SOX2—previously known to be mutated in hereditary human esophageal malformations, to be necessary for normal esophageal squamous development, to promote proliferation of basal tracheal cells and to co-operate in induction of pluripotent stem cells -- acts as an amplified oncogene in squamous cell carcinomas (SCC) of the lung and esophagus. We identified SOX2 at a peak of genomic amplification on chromosome 3q26.33 in SCCs of both the lung and esophagus but did not find it to be significantly amplified in adenocarcinomas from these tissues. Tumors with SOX2 amplification showed higher SOX2 mRNA expression, and suppression of SOX2 by RNAi in lung and esophageal SCC cell lines revealed that SOX2 expression is required for proliferation and anchorage-independent growth. Furthermore, ectopic expression of SOX2 cooperated with FOXE1 or FGFR2 to transform immortalized tracheobronchial epithelial cells. SOX2-driven tumors showed expression of markers of both squamous differentiation and pluripotency. These observations identify SOX2 as a novel lineage survival oncogene in lung and esophageal SCC and suggest novel connections between development, pluripotency and carcinogenesis.