Kappa light chain antibody can be used for the identification of leukemias, plasmacytomas and certain non-Hodgkin's lymphomas. Kappa light chain contains one immunoglobulin-like domain. The EU sequence has the INV allotypic marker, Ala-45 and Val-83. The ROY sequence has the INV allotypic marker, Ala-45 and Leu-83.