It has been determined that nerve growth factor binds to a cell surface protein of human neural crest origin having a molecular weight of about 75,000 daltons. New monoclonal antibodies specifically imunoprecipitate these receptor molecules, and also inhibit binding of the hormone to the receptor. These monoclonal antibodies show significantly higher reactivity with primary and metastatic melanoma cell lines than with melanocytes. The antibodies are used as the basis of a method of diagnosing neural crest disease.