To this end, cells were cultured in the presence or absence of exogenous PDGF (100 ng/ml); a cell-free flow-based adhesion assay was employed to compare the adhesion of microspheres coated with CD44 immunopurified from either colon carcinoma cells (LS174T) which primarily express CD44v [17], [18], or human myeloid cells (HL60) which only express CD44s [17] to immobilized fibrin under flow. This evidence concerns the gene CD44 and colon carcinoma.