title: Aberrant Expression of Napsin A in Breast Carcinoma With Apocrine Features.
abstract: An incidental finding of napsin A-positive breast carcinoma with apocrine features during workup for metastatic cancer in an axillary lymph node led to our investigation of the incidence of napsin A expression in breast carcinomas, focusing on those with apocrine features. We included 97 cases of breast carcinomas and performed immunohistochemistry with napsin A, GATA-3, thyroid transcription factor-1, and GCDFP-15. There was a statistically significant difference between apocrine and nonapocrine cases with respect to polyclonal napsin A H-scores (P < .00152), monoclonal napsin A H-scores (P < .00631), GATA-3 H-scores (P < .00029), and GCDFP-15 H-scores (P < .00251). Of the 49 cases of apocrine carcinoma, monoclonal napsin A antibody was positive in 66.7% of cases, including in 7 (14.6%) that showed 3+ staining. The majority of nonapocrine cases were negative (62.5%) or weakly (1+) positive (29.2%), with none exhibiting 3+ strength. It is important for pathologists to be aware that breast carcinomas with apocrine features can express napsin A.
authors: Hofstra Northwell School of Medicine, Lake Success, NY, USA tvitkovski@nshs.edu.
authors: Taisia
authors: T
authors: Vitkovski
authors: New York University School of Medicine, New York, NY, USA.
authors: Shweta
authors: S
authors: Chaudhary
authors: Hofstra Northwell School of Medicine, Manhasset, NY, USA.
authors: Cristina
authors: C
authors: Sison
authors: Hofstra Northwell School of Medicine, Lake Success, NY, USA.
authors: Mansoor
authors: M
authors: Nasim
authors: Hofstra Northwell School of Medicine, Lake Success, NY, USA.
authors: Michael John
authors: MJ
authors: Esposito
authors: Hofstra Northwell School of Medicine, Lake Success, NY, USA.
authors: Tawfiqul
authors: T
authors: Bhuiya
mesh_terms: D016282:Aspartic Acid Endopeptidases / Q000032:analysis / Q000096:biosynthesis*; D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000175:diagnosis / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000175:diagnosis / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry
chemical_list: D014408:Biomarkers, Tumor; D016282:Aspartic Acid Endopeptidases; C498549:NAPSA protein, human
keywords: apocrine; breast; napsin A