Immunohistochemical analysis of estrogen receptors in feline mammary gland benign and malignant lesions: comparison with biochemical assay.
Estrogen receptors (ER) were determined by both the biochemical dextran-coated charcoal (DCC-ER) and the immunohistochemical Avidin biotin-peroxidase complex (IHC-ER) methods in proliferative mammary lesions collected from 37 cats: 20 malignant tumors without metastasis at first presentation, seven malignant tumors with lung and/or lymph node metastases and 10 benign tumors and dysplasias. Total number of samples analyzed by both methods was 44. The DCC-ER method was applied to frozen tissue samples and the IHC-ER method was applied to neutral buffered formalin-fixed, paraffin wax-embedded tissue samples by using the NCL-6F11 monoclonal antibody. Biochemically, 21 (47.7%) cases had equal or more than 5 fmol/mg of protein (standard positivity threshold). Immunohistochemically, 11 (25%) cases were scored positive, the percentage of positive nuclei being statistically linked to the intensity of immunostaining. Normal mammary gland tissue (13 cases) and/or dysplastic areas (5 cases) found in the surroundings of the main lesion were IHC-ER positive in 76.9% and 40% of the cases, respectively. Concordance between DCC-ER and IHC-DCC was 72.7% and the results of the DCC and the IHC-ER methods were significantly correlated (P < 0.05) by the chi2 test. Specificity (true negatives) and sensitivity (true positives) of the ICH-ER method were 95.6% and 47.6%, respectively. One out of eleven DCC-ER positive and IHC-ER negative discordant cases (9.09%) was a DCC-ER false positive, because the surrounding normal mammary gland tissue was IHC-ER positive. The remaining 10 cases had ER content values equal or lower than 23 fmol/mg of protein, a figure that could represent the sensitivity threshold of the immunohistochemical method employed.
de las Mulas
J M
JM
Department of Comparative Pathology, Veterinary School, University of Córdoba, Spain.
van Niel
M
M
Millán
Y
Y
Blankenstein
M A
MA
van Mil
F
F
Misdorp
W
W
D000230:Adenocarcinoma / Q000175:diagnosis / Q000556:secondary / Q000662:veterinary; D000818:Animals; D000911:Antibodies, Monoclonal; D002291:Carcinoma, Papillary / Q000175:diagnosis / Q000556:secondary / Q000662:veterinary; D002371:Cat Diseases / Q000175:diagnosis*; D002415:Cats; D004108:Dilatation, Pathologic / Q000175:diagnosis / Q000662:veterinary; D005260:Female; D006965:Hyperplasia / Q000175:diagnosis / Q000662:veterinary; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000556:secondary; D008207:Lymphatic Metastasis; D008321:Mammary Glands, Animal / Q000737:chemistry; D015674:Mammary Neoplasms, Animal / Q000737:chemistry / Q000175:diagnosis* / Q000473:pathology; D011869:Radioligand Assay / Q000662:veterinary; D011960:Receptors, Estrogen / Q000032:analysis* / Q000737:chemistry; D012680:Sensitivity and Specificity
D000911:Antibodies, Monoclonal; D011960:Receptors, Estrogen