An evaluation of different Cripto-1 antibodies and their variable results

Cripto-1 is a protein expressed during embryonal development and has been linked to several malignant processes in cancer. Since the discovery of cripto-1 in the late 1980s, it has become a subject of biomarker investigation in several types of cancer which in many cases relies on immunolocalization of cripto-1 using antibodies. Investigating cripto-1 expression and localization in primary glioblastoma cells, we discovered nonspecific binding of cripto-1 antibody to the extracellular matrix Geltrex. A panel of four cripto-1 antibodies was investigated with respect to their binding to the Geltrex matrix and to the cripto-1 positive control cells NTERA2. The cripto-1 expression was varied for the different antibodies with respect to cellular localization and fixation methods. To further elaborate on these findings, we present a systematic review of cripto-1 antibodies found in the literature and highlight some possible cross reactants with data on sequence alignments and structural comparison of EGF domains.