Sequential changes in gene expression profiles in breast cancers during treatment with the aromatase inhibitor, letrozole.

W R Miller, A Larionov, T J Anderson, D B Evans, J M Dixon

Edinburgh Breast Unit Research Group, Western General Hospital, Edinburgh, UK. w.r.miller@ed.ac.uk

The pharmacogenomics journal 2012 Feb

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The study aim was to identify early (within 14 days) and late changes (by 3 months) in breast cancer gene expression profiles associated with neoadjuvant therapy with letrozole. RNA from sequential tumour biopsies in 54 patients was analyzed on microarrays; changes were determined by frequency, magnitude and significance analyses. Substantially more genes were changed at 3 months (1503) than at 14 days (237). Early changed genes were associated with cell cycle (downregulation), blood vessel development and extracellular matrix (upregulation); late changes included 'cellular metabolic process', 'generation of precursor metabolites and energy' (decreased) and 'cell adhesion' 'biological adhesion' (increased). A striking difference between the early and late changes was the general location of downregulated genes-nuclear structures at 14 days and mitochondria after 3 months. These changes in gene expression profiles provide a new and important database by which to understand molecular mechanisms of letrozole in breast cancers.

Citation

W R Miller, A Larionov, T J Anderson, D B Evans, J M Dixon. Sequential changes in gene expression profiles in breast cancers during treatment with the aromatase inhibitor, letrozole. The pharmacogenomics journal. 2012 Feb;12(1):10-21