We determined differentially expressed genes in HT29 human colon cancer cells, both after short treatment with methotrexate (MTX) and after the resistance to MTX had been established. Screening was performed using Atlas Human Cancer cDNA arrays. The analysis was carried out using Atlasimage software. Among the differen-tially expressed genes we chose for further validation were inosine mono-phosphate dehydrogenase type II (IMPDH2), inosine monophosphate cyclohydrolase and survivin as up-regulated genes, and topoisomerase I (TOP1) and vimentin as down-regulated genes. .
