ST8SIA4 and metastatic neoplasm: Some important findings of this study are: (i) ldlD-14 cells provide a useful model for studying and comparing the functions of NCAM and PSA-NCAM; (ii) in our model, up-regulation of NCAM-140 enhanced cell proliferation, motility, and migration, which are characteristic processes of metastatic tumors; (iii) NCAM bearing PSA was associated with enhanced cell proliferation, migration and aberrant adhesion, suggesting that PSA overexpression promotes metastasis; (iv) different polysialyltransferases (STX vs. PST) have differing effects on cell proliferation, adhesion and migration.