... International) and enhanced with SuperSignal Chemiluminescence kit(Pierce Biotechnology).Immunohistochemistry and scoring To investigate the significance of Her2 and Her3 expres-sion in HNSCC, 4-micron ... notshown). Her2 staining was scored based on the scoringsystem applied to breast cancers, with scores of 0,+1,+2, +3 for increas ing intensity and “ continuity” of stain-ing of the cell membrane[17]. ... transmembrane domain, and an intracytoplas mic tyrosine kinase domain[3-5]. Ligandbinding to these receptors induces the formation of * Correspondence: genejock@helix.nih.gov† Contributed equally1Tissue...