title: Neuroendocrine differentiation in carcinoma of the breast. Tyramide signal amplification discloses chromogranin A-positive tumour cells in more breast tumours than previously realized.
abstract: The aim of the study was to determine if, by means of tyramide signal amplification (TSA), the presence of chromogranin A (CgA)-positive tumour cells could be demonstrated in breast cancer cases found to be negative by conventional immunohistochemical staining. Sections from 44 cases of breast cancer (28 infiltrating ductal carcinomas, 2 lobular carcinomas, 4 ductal carcinomas in situ (DCIS), 7 lobular carcinomas in situ (LCIS), and 3 mucinous carcinomas) were stained for CgA by conventional immunohistochemical methods and by immunohistochemistry with TSA. The sections were also histologically graded and their oestrogen receptor (ER), progesterone receptor (PgR) and HER-2 oncogene status was recorded. Five of the tumours showed CgA-positive staining with the polyclonal antibody 430 with conventional methods. Thirty cases showed CgA-immunoreactive tumour cells after immunohistochemical staining with the polyclonal antibody 430 with TSA. However, eight of these also showed faint staining with the negative control antibody X0936 with TSA. One case showed immunopositivity for CgA using a monoclonal antibody without tyramide amplification and only a further two cases were positive when TSA was applied. The presence of CgA appears to be associated with a lower histological grade and may be more often found in oestrogen receptor-positive tumours.
authors.affiliation: Norwegian University of Science and Technology, Department of Laboratory Medicine, St. Olavs Hospital, Trondheim University Hospital, N-7006 Trondheim, Norway. anna.bofin@medisin.ntnu.no
authors.forename: A M
authors.initials: AM
authors.lastname: Bofin
authors.forename: G
authors.initials: G
authors.lastname: Qvigstad
authors.forename: C
authors.initials: C
authors.lastname: Waldum
authors.forename: H L
authors.initials: HL
authors.lastname: Waldum
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000378:metabolism; D000906:Antibodies; D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000378:metabolism; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000378:metabolism; D018275:Carcinoma, Lobular / Q000378:metabolism; D018278:Carcinoma, Neuroendocrine / Q000378:metabolism* / Q000473:pathology; D002454:Cell Differentiation; D053379:Chromogranin A; D002864:Chromogranins / Q000032:analysis*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D012680:Sensitivity and Specificity; D014439:Tyramine
chemical_list: D000906:Antibodies; D014408:Biomarkers, Tumor; C506150:CHGA protein, human; D053379:Chromogranin A; D002864:Chromogranins; D014439:Tyramine