BCA (breast cancer antigens): different purification extraction methods

Various types of extraction were tested to increase the immunological yield of BCA, a CEA-like primary breast cancer associated carcinoma antigen. To allow a comparison, the different extraction techniques were applied to only one breast tumour. The comparison of the various systems was based on two parameters: protein yield and immunological activity, assayed in a RIA 125I CEA-anti CEA system. The following extraction methods were described and compared in this paper: 3M KCl; 1N HClO4; neutral pH extraction (PBS) in the absence and presence of various detergents (anionic, neutral and cationic), basic pH extraction (1N NaOH) and acid pH extraction (1.5M acetic acid) in the presence of urea and various detergents. The more significant systems were applied also to the extraction of CEA, from colonic adenocarcinoma liver metastases. The best results for both the antigens studied were obtained by using neutral detergents (1% NP 40) at neutral pH.