A Tissue Microarray Immunohistochemical Study of Gynecologic Versus Breast Primary
TC Pereira, SM Share, KM Jasnosz, AV Magalhaes, JF Silverman. Allegheny General Hospital, Pittsburgh, PA; Universidade de Brasilia, Brasilia, Brazil
Background: In the work-up of metastatic carcinoma of unknown primary, some of the immunohistochemical (IHC) markers commonly used for a gynecologic (GYN) primary such as estrogen (ER) and progesterone receptor (PR) proteins are also reactive in breast primaries. Therefore, an expanded panel can be of value in indeterminate cases in the work-up of metastases of unknown primary when the differential diagnosis is a GYN versus a breast primary and/or a patient with either a known GYN or breast primary and a second primary needs to be excluded. For this differential, we evaluated a panel including ER, PR, GCDFP-15, CDX2, villin, Pax-2, mammaglobin and WT1 in a tissue microarray of breast carcinomas and GYN carcinomas including ovary and endometrium.
Design: We performed immunostains in a total of 171 cases: 40 endometrium, 45 ovary, and 86 breast, including different histologic types on each. We scored as positive if at least 5% of the cells were staining, with nuclear staining for ER, PR, CDX-2, Pax-2 and WT-1; cytoplasmic staining for GCDFP-15 and mamaglobin; and membranous staining for villin. We calculated the percentage of positive cases after excluding cases in which the microarray "dot" did not contain tumor cells or was not present in that particular slide.