Bronchioloalveolar carcinoma (BAC) is a sub-type of adenocarcinoma of the lung that commonly occurs in middle-age women without a history of smoking. Patients with BAC often present with advanced disease and treatment options are very limited. We hypothesize that novel peptide ligands can be identified for cell-surface receptors specific for BAC using the methods of ‘one-bead one-peptide’ combinatorial chemistry and ‘cell-growth-on-bead’ assay. We believe that these novel peptide ligands potentially can be developed into effective diagnostic and therapeutic agents for improving survival of patients with BAC. The specific aims of this proposal are formulated as follows: 1. To design and synthesize one-bead one-peptide combinatorial libraries for screening novel peptide ligands specific for BAC cells; 2. To screen, from these libraries, for novel peptide ligands that specifically promote cell adhesion of BAC cells; 3. To study the structure-activity of these novel peptide ligands in order to identify motifs essential for cell adhesion; 4. To modify these novel ligand peptides to optimize their biological activity and pharmacokinetic property; 5. To investigate tumor specificity of these peptide ligands using human tumor specimens; and 6. To identify cell-surface receptors specific for interaction with the novel peptide ligands in BAC. The knowledge gained from this project will support development of these novel peptide ligands into potential diagnostic and therapeutic agents for BAC.