c-erbB-2 expression indifferent histological types ofinvasive breast carcinoma

Sections of149breast carcinomas were examinedfortheover-expression of c-erbB-2oncoprotein usingtheavidinbiotin immunoperoxidase technique and twodifferent specific antibodies. These included thepolyclonal antibody 21N andthemonoclonal antibody 4D5.The tumoursweredividedintotwo main groups.Thefirst included 75casesof invasive ductaland classic invasive lobular carcinomas. Thesecondgroup consisted of74caseswithhistological typesknowntohavea goodprognosis, including mucinous, alveolar variant of invasive lobular, medullary, tubular, cribriform and papillary carcinomas. Fifteen (20%)tumoursofthefirst group werepositive withthetwo antibodies. Fourteen ofthese wereoftheductal type andonewasamixedinvasive ductal and lobularcarcinoma.Ten of thepure ductalcaseshad areas of comedo carcinoma. Theintraductal elements in afurther tumourwerepositively stained with21N antibodyonly.None ofthe secondgroup of tumours,which includedhistological typesknown to havegoodprognosis, stained with4D5, although onemucinouscarcinoma was positively stained with21N. Thesefindings suggest thatininvasive breastcarcinomaimmunostaining for c-erbB-2 ismainly seeninasubgroup of ductaltumours,and thatalmostall otherhistological types, especially those associated withgoodprognosis, lackthis expression.