The present invention provides progastrin-binding molecules specific forprogastrin that do not bind gastrin-17(G17), gastrin-34(G34), glycine-extendedgastrin-17(G17-Gly), or glycine-extended gastrin-34(G34-Gly). Further, theinvention provides monoclonal antibodies (MAbs) selective for sequences at theN-terminus and the C-terminus of the gastrin precursor molecule, progastrinand the hybridomas that produce these MAbs. Also provided are panels of MAbsuseful for the detection and quantitation of progastrin and gastrin hormonespecies in immuno- detection and quantitation assays. These assays are usefulfor diagnosing and monitoring a gastrin-promoted disease or condition, or formonitoring the progress of a course of therapy. The invention further providessolid phase assays including immunohistochemical (IHC) and immunofluorescence(IF) assays suitable for detection and visualization of gastrin species insolid samples, such as biopsy samples or tissue slices. The progastrin-bindingmolecules are useful therapeutically for passive immunization againstprogastrin in progastrin-promoted diseases or conditions. Also provided aresurrogate reference standard (SRS) molecules that are peptide chains of fromabout 10 to about 35 amino acids, wherein the SRS molecule comprises at leasttwo epitopes found in a protein of interest of greater than about 50 aminoacids. Such SRS molecules are useful as standards in place of authenticproteins of interest.
