The LRIG1 gene (formerly LIG-1), recently cloned by us, displays structural similarities to the Drosophila Kek I gene. Kek I encodes a cell surface protein, Kekkon-1, which inhibits epidermal growth factor receptor-mediated signalling. We localized the LRIG1 gene to chromosome band 3p14.3, a region known to be deleted in various human cancers. In the present study LRIG1 gene expression was examined in different tumour cell lines and corresponding normal tissues by real-time RT-PCR. In many tumour cell lines, LRIG1 expression appeared absent or was down regulated compared to corresponding normal tissues. The results are consistent with LRIG1 being a tumour suppressor gene in humans. However, further studies are justified to elucidate the explicit role of LRIG1 as a negative regulator of oncogenesis.