Gastrin-releasing peptide receptor-mediated autocrine growth in squamous cell carcinoma of the head and neck

mediated autocrine growth appears to be an early marker of susceptibility to tobacco-related lung cancers. Because ex-pression of GRPR, however, has not been reported in squa-mous cell carcinoma of the head and neck (SCCHN), we investigated its expression and that of its ligand GRP in normal mucosa and SCCHN tissues and the involvement of these proteins in the proliferation of SCCHN cells. Methods: We assessed GRPR messenger RNA (mRNA) expression in specimens from 25 patients with SCCHN, six control non-cancer patients, and 14 SCCHN cell lines by use of quanti-tative reverse transcriptase–polymerase chain reaction. We used neutralizing GRP monoclonal antibody 2A11 to block the GRP–GRPR interaction in SCCHN cell lines and xeno-grafts and assessed the antibody’s effect on proliferation by counting cultured cells or measuring xenograft tumor vol