title: Napsin A is frequently expressed in clear cell carcinoma of the ovary and endometrium.
abstract: Napsin A is a reliable marker for pulmonary adenocarcinoma and is expressed in a subset of ovarian clear cell carcinomas (O-CCCs), endometrial (EM) CCCs, and endometrioid carcinomas (EC). We investigated napsin A levels in O-CCC and EM-CCC and compared these with levels in other nonmucinous ovarian carcinomas and EM-EC, respectively. Napsin A, thyroid transcription factor (TTF)-1, paired box (PAX) 8, and cancer antigen (CA) 125 expression was evaluated in 111 ovarian and uterine carcinoma cases (22 O-CCC, 15 EM-CCC, 13 ovarian EC (O-EC), 39 high-grade serous carcinoma [HGSC], and 22 EM-EC) using immunohistochemistry. Napsin A immunoreactivity was observed in 21 (95.5%) of 22 O-CCC and 10 (66.7%) of 15 EM-CCC cases but was rare in O-EC and EM-EC (7.7% and 4.5%) and undetectable in HGSC cases. Thyroid transcription factor 1 was not expressed in O-CCC but was detected in 1 (6.7%) of 15 EM-CCC, 3 (23.1%) of 13 O-EC, 2 (5.1%) of 39 HGSC, and 1 (4.5%) of 22 EM-EC cases. All 111 cases examined were positive for PAX8, whereas 3 (20.0%) of 15 of EM-CCC and 1 (4.5%) of 22 EM-EC cases were negative for CA125. There were no napsin A/TTF-1 double-positive cases, except for 1 EM-CCC, in which cells had a focal expression pattern. All napsin A- and/or TTF-1-positive cases expressed PAX8 and CA125. In conclusion, napsin A is frequently expressed in O-CCC and EM-CCC, rarely in O-EC and EM-EC, and never in HGSC cases. These findings confirm the importance of using a panel of antibodies that includes napsin A, TTF-1, and PAX8 when evaluating metastatic carcinomas of unknown origin, particularly when gynecologic and pulmonary adenocarcinomas are included in the differential diagnosis.
authors.affiliation: Department of Diagnostic Pathology, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan. Electronic address: m-iwamoto@chiba-u.jp.
authors.forename: Masami
authors.initials: M
authors.lastname: Iwamoto
authors.affiliation: Department of Diagnostic Pathology, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan. Electronic address: nakatani@faculty.chiba-u.jp.
authors.forename: Yukio
authors.initials: Y
authors.lastname: Nakatani
authors.affiliation: Department of Molecular Pathology, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan. Electronic address: fugo@faculty.chiba-u.jp.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Fugo
authors.affiliation: Department of Molecular Pathology, Chiba University Graduate School of Medicine, 1-8-1 Inohana, Chuo-ku, Chiba 260-8670, Japan. Electronic address: tkishi@faculty.chiba-u.jp.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kishimoto
authors.affiliation: Department of Pathology, Jikei University School of Medicine, 3-25-8 Nishishinbashi, Minato-ku, Tokyo 105-8461, Japan. Electronic address: kiyokawa@jikei.ac.jp.
authors.forename: Takako
authors.initials: T
authors.lastname: Kiyokawa
mesh_terms: D016282:Aspartic Acid Endopeptidases / Q000032:analysis*; D014408:Biomarkers, Tumor / Q000032:analysis*; D018394:CA-125 Antigen / Q000032:analysis; D002277:Carcinoma / Q000201:enzymology* / Q000473:pathology; D003937:Diagnosis, Differential; D016889:Endometrial Neoplasms / Q000201:enzymology* / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000032:analysis; D009687:Nuclear Proteins / Q000032:analysis; D010051:Ovarian Neoplasms / Q000201:enzymology* / Q000473:pathology; D000072636:PAX8 Transcription Factor; D051761:Paired Box Transcription Factors / Q000032:analysis; D011237:Predictive Value of Tests; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors / Q000032:analysis
chemical_list: D014408:Biomarkers, Tumor; D018394:CA-125 Antigen; C451759:MUC16 protein, human; D008565:Membrane Proteins; C000614412:NKX2-1 protein, human; D009687:Nuclear Proteins; D000072636:PAX8 Transcription Factor; C083325:PAX8 protein, human; D051761:Paired Box Transcription Factors; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors; D016282:Aspartic Acid Endopeptidases; C498549:NAPSA protein, human
keywords: Clear cell carcinoma; Endometrial carcinoma; Napsin A; Ovarian carcinoma; PAX8