Interestingly, among the most significantly down-regulated genes, RPS4Y1, DDX3Y, EIF1AY, ZFY and USP9Y, were located on the Y chromosome. The five PSG genes increased in Cr transformed cells were also localized in a cluster on chromosome 19. It is not clear whether these changes were gene-specific or loci-specific. Cr exposure has been shown to induce chromosome instability, including both numerical and structural aberrations, which might cause similar expression changes in multiple genes clustered in a chromosomal region. It is worth noting that all six Cr transformed cell lines SB431542 301836-41-9 exhibited similar changes in these two sub-groups of genes. Further analysis of chromosome damage and aberration as well as epigenetic mapping of these Cr transformed cells will help us to understand the underlying mechanism for these gene expression changes. A major group of genes altered in Cr transformed cells were genes related to cell junction, a type of specialized structure mediating the contact between cells or between cells and extracellular matrix. In epithelial cells, there are four major types of cell-cell junctions: tight junction, gap junction, adherens junction and desmosomes. The major components of the desmosome complex, DSC2, DSC3, and Perp, are increased approximately 8-, 40- and 5- fold, respectively, in Cr transformed cells. In addition, CDH6,Tasocitinib a type II classical cadherin involved in adherens junction, and CLDN1, the major protein for tight junction, are also up-regulated 4- and 2-fold, respectively, in Cr transformed cells. L1CAM, the L1 cell adhesion molecule, increased 4.7-fold in Cr transformed cells. Thus, genes associated with cell junction were up-regulated in Cr transformed cells. In contrast to up-regulation of genes related to cell-to-cell contact, many genes involved in focal adhesion, a major type of cell junction mediating cell and extracellular matrix interaction, were decreased in Cr transformed cells. Integrins, the key component of focal adhesion, are transmembrane receptors that recognize and bind to most extracellular matrix proteins, such as collagens, fibronectin, and laminins. Each integrin molecule is a heterodimer formed from 9 beta and 25 alpha subunits. Cr transformed cells exhibited decreased integrin alpha 5, beta 3 and beta-like 1 subunits, but increased alpha 4 subunit. Similarly, the major component of the extracellular matrix, the ligands of the integrin receptor, were also decreased in Cr transformed cells: COL4A1, COL5A1, COL5A2, LAMB1 and LAMC2. Moreover, Fibulin-1, an extracellular matrix protein often associated with fibronectin, which was able to inhibit the motility of a variety of cell types, decreased 3.6-fold in transformed cells. Fibrillin-1, a large extracellular matrix glycoprotein that sequestered TGFb via an interaction with latent TGFb binding protein, was also down-regulated in Cr transformed cells.