The activity of growth factors is crucial for tumor progression. We previously characterized a secreted fibroblast growth factor–binding protein (FGF-BP1) as a chaperone molecule, which enhances the biological functions of FGFs by releasing FGFs from the extracellular matrix. Here, we characterize the frequency and pattern of FGF-BP1 expression during the malignant progression of pancreas and colorectal carcinoma. For this, we generated monoclonal antibodies that detect FGF-BP1 protein in formalin-fixed, paraffin-embedded tissues and applied in situ hybridization to detect FGF-BP1 mRNA in adjacent tissue sections. FGF-BP1 protein and mRNA were found up-regulated (>70% positive) in parallel (r = 0.70, P < 0.0001) in colon adenoma (n = 9) as well as primary (n = 46) and metastatic (n = 71) colorectal cancers relative to normal colon epithelia (all P < 0.0001, versus normal). Similarly, pancreatitis (n = 17), pancreatic intraepithelial neoplasia (n = 80), and pancreatic adenocarcinoma (n = 67) showed a significant up-regulation of FGF-BP1 compared with normal pancreas (n = 42; all P < 0.0001, relative to normal). Furthermore, the biological activity of FGF-BP1 is neutralized by one of the antibodies, suggesting the potential for antibody-based therapeutic targeting. We propose that the up-regulation of the secreted FGF-BP1 protein during initiation of pancreas and colon neoplasia could make this protein a possible serum marker indicating the presence of high-risk premalignant lesions. (Cancer Res 2006; 66(2): 1191-8)