The present invention relates to the identification of a novel role of Nr-CAM in cell transformation and aberrant cellular proliferation. In particular, the present invention relates to the altered gene expression of Nr-CAM in a number of primary tumors and cell lines derived from tumors, in addition to, the altered gene expression of ligands for Nr-CAM. Further, the present invention relates, in part, to the Applicants' surprising discovery that the inhibition of Nr-CAM gene expression or the inhibition of Nr-CAM activity in transformed cells reverses the transformed phenotype.