Development and clinical evaluation of a multi-purpose mAb and a sandwich ELISA test for hepatoma-derived growth factor in lung cancer patients

Hepatoma-derived growth factor (HDGF) is closely related to aggressive tumor behavior and could be a broader biomarker for cancer prognosis and diagnosis. The goal of this study is to develop a sandwich ELISA system to test if HDGF can be detected in serum samples. We produced an anti-HDGF monoclonal antibody designated 2F12 using recombinant human HDGF protein. The specificity of 2F12 mAb was characterized by western blotting, immunohistochemistry (IHC), immunofluorescent staining (IF) and immunoprecipitation (IP). The results showed that 2F12 recognized HDGF in both native and denatured form, and can be used for multiple purposes. We have found that HDGF is also expressed in several cancers unreported previously by IHC staining on tumor cell array sections. In addition, we have developed a sandwich ELISA assay using mAb 2F12 and rabbit anti-HDGF polyclonal antibody, and validated the assay using normal serum and non-small cell lung cancer (NSCLC) serum samples. The sensitivity of this assay is 0.5 ng/ml and the linear range is 0.5–32 ng/ml. The HDGF average level in serum samples from lung cancer patients is significantly elevated relative to that from healthy controls, 9.43 ± 6.13 ng/ml versus 4.36 ± 2.50 ng/ml (p = 1.12E–10).