The receptor tyrosine kinase known as RON appears to play a role in the progression of human carcinomas, and is associated with a poor patient prognosis. Our current study demonstrates that RON expression in MCF-10A breast epithelial cells lead to an alteration of cell-surface hyaluronan compared to the parental cells. We found that hyaluronan was important for initial cell attachment to poly-D-lysine-coated coverslips, but did not contribute to the process of cell spreading. Previous data implied that the Src kinase was important for spreading but not the initial attachment of 10A cells, and here we demonstrate Src activation was also not necessary for hyaluronan production in these cells. (C) 2009 Elsevier Inc. All rights reserved.