The aims of the present study were therefore to establish whether TNC-AD1 and/or TNC-AD2 domains represent tumour-associated isoforms in breast cancer, to determine whether expression of these isoforms correlates with clinicopathological features and tumour subtypes identified by immunohistochemical profiling [33,34], and to use in vitro studies to investigate the functional significance of a TNC isoform containing the AD1 domain to tumour cell behaviour. The gene discussed is TNC; the disease is breast carcinoma.