TWIST1 over-expression results in over-representation of common GO categories related to mesenchymal phenotype and invasion. To characterize changes in gene expression due to TWIST1 over-expression, we compared global gene expression in vector control and TWIST1 over-expressing SNB19 and T98G cells using the Affymetrix GeneChip platform. The analysis revealed many common categories identified by GoMiner (FDR cut-off level <0.1) that are related to mesenchymal function and invasion (cell adhesion, extracellular matrix, cell migration, cell motility and locomotion, and actin cytoskeleton organization) as well as cell-line specific categories consistent with TWIST1 function (transcription and organ development and morphogenesis, e.g.). The number of up- and down-regulated genes in each category is shown. The individual genes that comprise each category are provided in Additional file 4, Table S1.