The new Sar11-modified [111In]In-AU-RM26-M1 successfully targeted the experimental PC-3 tumors and the GRPR-rich pancreas in mice via a GRPR-specific process, as verified by the significant decrease in tumor and pancreas uptake in the mice that received a high excess of a GRPR-specific peptide for an in vivo GRPR blockade. The gene discussed is GRPR; the disease is neoplasm.