• gene expression
• microarray technology

There is no doubt that gene expression studies based on evaluating mRNA levels for single or multiple genes of interest in human lung biopsy tissue have had a major impact on our understanding of the molecular mechanisms underlying respiratory disease. The recent advent of microarray technology has added further impetus to the central paradigm that mRNA quantification in lung tissue can shed light on pathogenesis and identify new targets for therapeutic intervention. This technology is now so advanced that it allows the parallel monitoring of entire genomes using microarrays with a surface area equivalent to just a few square centimetres and as little as 5 μg RNA starting material.

Since its first application in the mid 1990s,¹ microarray technology has been applied to all aspects of biomedical research with over 60 papers in respiratory research alone. It has been successfully used for the classification and molecular diagnosis of lung cancer,² the identification of potential target genes for therapeutic intervention in idiopathic pulmonary fibrosis,³ mechanistic studies in animal models of asthma⁴ and pulmonary fibrosis,⁵ and for profiling lung development.⁶ Global expression profiling of cellular responses in vitro has provided new insights into the transcriptional programs involved in cytokine signalling,⁷ growth arrest and apoptosis,⁸ and it is already enabling us to understand the operation of functional gene networks.