Differences in gene expression levels between early and later stages of human lung development are opposite to those between normal lung tissue and non-small lung cell carcinoma.

We, for the first time, directly compared gene expression profiles in human non-small cell lung carcinomas (NSCLCs) and in human fetal lung development. Previously reported correlations of gene expression profiles between lung cancer and lung development, deduced from matching data on mouse development and human cancer, have brought important information, but suffered from different timing of mouse and human gene expression during fetal development and fundamental differences in tumorigenesis in mice and humans. We used the suppression subtractive hybridization technique to subtract cDNAs prepared from human fetal lung samples at weeks 10-12 and 22-24 and obtained a cDNA library enriched in the transcripts more abundant at the later stage. cDNAs sequencing and RT-PCR analysis of RNAs from human fetal and adult lungs revealed 12 differentially transcribed genes: ADH1B, AQP1, FOLR1, SLC34A2, CAV1, INMT, TXNIP, TPM4, ICAM-1, HLA-DRA, EFNA1 and HLA-E. Most of these genes were found up-regulated in mice and rats at later stages than in human lung development. In surgical samples of NSCLC, these genes were down-regulated as compared to surrounding normal tissues and normal lungs, thus demonstrating opposite expression profiles for the genes up-regulated during fetal lung development.