Drebrin: A new oncofetal biomarker associated with prognosis of lung adenocarcinoma.
With the aim of searching for novel oncofetal tumor biomarkers of lung adenocarcinoma other than carcinoembryonic antigen (CEA) and alpha-fetoprotein (AFP), we developed a strategy involving monoclonal antibodies generated from embryonic tissue of miniature swine. Using immunohistochemistry, we selected suitable hybridoma clones that were reactive against swine fetal lung but not adult lung using tissue microarray loading of human normal lung, lung cancer, and fetal and adult swine tissues. The selected clones included several that were uniquely reactive against both swine fetal lung and human lung adenocarcinoma, and protein microarray revealed that the antigen they recognized was "drebrin" (DBN1). We then examined the association between the pattern of drebrin expression and the clinicopathological characteristics of lung adenocarcinoma using surgically resected samples of human lung adenocarcinoma. Two hundred formalin-fixed and paraffin-embedded tumor samples were immunostained for drebrin using clone B246, one of the clones that were reactive against drebrin. The cases were divided into those with strong (n=85) and weak (n=115) drebrin expression. In terms of disease-free survival, cases showing strong drebrin expression had a significantly poorer prognosis than those with weak drebrin expression (p=0.033). The present findings indicate that "drebrin" is a unique oncofetal protein that can be applied as a new biomarker of lung adenocarcinoma.