Genes encoding adhesion molecules, MHC class I and class II, and cytoskeleton binding proteins were up-regulated in monocytes derived from ATL patients. The gene expression of monocytes from 3 ATL patients were compared with the gene expression of monocytes derived from 3 normal healthy donors. The monocytes were purified using negative selection. cDNA from ATL monocytes or normal monocytes was labeled with Cy5 and hybridized with human universal reference cDNA labeled with Cy3. Red indicates Cy5/Cy3 ratio more than 1, green indicates Cy5/Cy3 ratios less than 1, black indicates no significant change in gene expression, and gray indicates the spot did not meet data selection criteria. These ratios were depicted according to the color scale shown at the bottom. Three sets of functional related genes, including genes encoding adhesion molecules, MHC class I and MHC class II gene, and genes encoding cytoskeleton binding proteins, which had at least 2-fold increases in the ATL monocytes.