Evaluation of Annexin A2 as a novel diagnostic serum biomarker for lung cancer.

Annexin A2 (ANXA2) is a 36 kDa protein which orchestrates multiple biologic processes and clinical associations, especially in cancer progression. It is important to establish a specific and sensitive ANXA2 enzyme-linked immunosorbent assay (ELISA) for the study of ANXA2 functions and its clinical application. Therefore, we prepared a polyclonal antibody (PAb) in rabbits and a monoclonal antibody (MAb) in mices immunized with a recombinant ANXA2 protein. Based on our self-made MAb and PAb, highly specific and sensitive ELISA was developed. The detection limitation of ANXA2 was 10 ng/mL and the linear dynamic range was between 10 and 500 ng/mL. Using the established ELISA, we detected ANXA2 protein in human serum. It was found that soluble ANXA2 concentration in serum samples from 42 lung cancer patients was significantly higher than that from 43 healthy individuals (p< 0.01). Our data provides a new approach for detecting soluble ANXA2, especially in large ongoing and future clinical studies.