INCREASED SERUM CA125 LEVELS IN PLASMA-CELL DYSCRASIAS

We report 2 cases of plasma cell dyscrasia presenting with significant ly elevated serum CA125 levels. The serum levels of CA125 from these p atients correlated well with their serum M-protein levels, One patient had an IgG-kappa type extramedullary plasmacytoma with the culture su pernatant from lymph node plasma cells showing a considerably high lev el of CA125 activity. The serum IgG fraction purified using a protein A column was devoid of any detectable CA125 activity, negating that th e serum IgG M-protein from this patient might respond with a false-pos itive result in the CA125 immunoradiometric assay. The other patient h ad an IgG-lambda type plasma cell leukemia with the culture supernatan t from peripheral mononuclear cells also showing a high level of CA125 activity. These observations may suggest that in plasma cell dyscrasi as the CA125 antigen is spontaneously produced by tumor cells.