Immunohistochemistry assessments on pulmonary adenocarcinoma surgical specimens demonstrated that SP5-2 has a clinical potential as imaging probes to identify NSCLC or drug delivery agents for the treatment of NSCLC. Both PC5-2 and biotinlabeled SP5-2 detected pulmonary adenocarcinoma surgical specimens in our experiments (Fig. 1D) . Seventy-five percent (27/36) of pulmonary adenocarcinoma specimens from 36 patients expressed a target molecule that was recognized by the peptide (Table S1 ). SP5-2, but not MP5-2, competed with PC5-2 for binding to pulmonary adenocarcinoma surgical specimens (Fig. 1D) , which further confirmed the specificity of this targeting ligand.