The Xema Corporate Group started in February 1993 as the private company Xema Co. Ltd. in Moscow, Russia. Over the course of twenty years, Xema has developed from a small-scalecontract manufacturer of human antigen proteins to one of the world’s leading biological companies in providing tumor marker antigens and corresponding monoclonal antibodies. With our broad hybridoma collection, Xema now has the ability for the large-scale production of purified monoclonal antibodies for in vitro diagnostic use.