Abstract: HGF, also known as “Scatter Factor”, is a mesenchymal cytokine that acts on epithelial and endothelial cells by promoting a highly integrated biological program, hereafter referred to as “invasive growth”. This program involves coordinated control of basic cellular functions including dissociation and migration (“scattering”), invasion of extracellular matrix, proliferation, prevention of apoptosis and polarization. As a consequence, complex developmental processes take place, such as branched morphogenesis of epithelia and angiogenesis. Oncogenic activation by overexpression or point mutation of the gene encoding the tyrosine kinase receptor for HGF, c-MET, is involved in the progression of tumors towards the invasive-metastatic phenotype. To identify genes involved in Met-driven invasive growth, we explored the transcriptional response of mouse liver cells to HGF at different time points. Two different microarray platforms were adopted, consisting respectively of high-density spotted cDNAs (Incyte) and in-situ synthesized oligonucleotides (Affymetrix). Global exploration of 25’000 gene transcripts yielded over 1500 transcriptionally regulated sequences, corresponding to genes involved in the control of the basic biological functions underlying the invasive growth program: transcription, signal transduction, apoptosis, proliferation, cytoskeleton organization, motility and adhesion. Joint analysis of the data obtained by the two platforms allowed identification of genes with more consistent and reproducible regulation. Meta-analysis on genomic expression datasets obtained from breast carcinoma showed that expression of genes belonging to the HGF signature is correlated to cancer progression.