Detection bymonoclonal antibody ofcarbohydrate antigen CA 50inserumofpatients withcarcinoma

A solidphaseradioimmunoassay was devisedfor measuring thevalueofthecarcinomaassociated carbohydrateantigen CA 50inserumbasedontheuseofa specific monoclonal antibody (C50).Samplesofserum from259patients withcarcinoma, 114patients withother malignancies orinflammatory diseases, and150healthy controls wereexamined.SerumvaluesofCA 50exceedingthemean plusthreestandard deviations forcontrol samplesfromblooddonorswerefoundina highproportionof patients withcolorectal adenocarcinomas (50%ofthosewithearly, localised tumoursand75%of advancedcases),othergastrointestinal carcinomas (69%), uterine cancer(75%ofthosewithcorporeal and 88% ofthosewithcervical cancer), prostatic cancer (90%), lungcancer(52%), andbreast, ovarian, kidney, and urinarybladdercarcinoma(26-67%). The CA 50 valuesin samplesfrom patients withinflammatory diseases, including ulcerative colitis, withrareexceptions(0-7%)werewithinthenormalrange,aswere thoseinpatients withvarioussarcomasandmalignant melanoma. Measuring serumvaluesofCA 50,whichisevidently a generalised carcinomaassociated antigen, may be