We have previously shown that transforming growth factor-beta1 (TGF-beta1) markedly stimulates the invasive capacity of rat ascites hepatoma AH130 W1 cells in vitro and in vivo. A differential hybridization procedure was used to isolate genes that were specifically up-regulated in TGF-beta1 treated W1 cells. Among ten independent cDNA clones, we focused on LMO7 and a variant isoform, LMO7S, that was generated by alternative splicing. LMO7 had PDZ and LIM domains, while LMO7S had only PDZ domain. TGF-beta1 up-regulated expression levels of LMO7 and LMO7S. LMO7 expression was up-regulated in the highly metastatic clone MM1.