Napsin A is a useful marker for metastatic adenocarcinomas of pulmonary origin.
OBJECTIVE
To address whether napsin A is useful for identifying metastatic adenocarcinomas of pulmonary origin.


RESULTS
Fifty-four cases of adenocarcinoma that metastasized from the lungs to various sites and 1762 cases of carcinoma from various organs were immunostained for napsin A, TTF-1, CK7, CK20 and CDX2 using tissue microarray. The expression patterns of napsin A and TTF-1 in metastatic pulmonary adenocarcinomas were compared with matched primary lung tumours. Napsin A and TTF-1 were expressed in 87.0% and 81.5% of the metastatic pulmonary adenocarcinomas, respectively. Although there was no significant difference in the positivity of napsin A and TTF-1 as a single marker in metastatic pulmonary adenocarcinomas, the expression scores for napsin A were much higher than those for TTF-1 (P < 0.001). Moreover, the positivity and expression scores of napsin A in primary pulmonary adenocarcinomas were maintained in metastatic adenocarcinomas better than TTF-1. Most non-pulmonary adenocarcinomas were negative for napsin A, except for renal cell carcinomas (13.4%), ovarian adenocarcinomas (7.1%) and uterine endometrial adenocarcinomas (14.5%). In particular, clear cell adenocarcinomas of ovary (68.8%) and uterus (66.7%) frequently expressed napsin A.


CONCLUSIONS
These data suggest that napsin A may be a useful marker for identifying metastatic adenocarcinomas of pulmonary origin in combination with TTF-1.
Department of Pathology, Seoul National University Hospital, Seoul, South Korea; Department of Pathology, Seoul National University College of Medicine, Seoul, South Korea.
Moon-Young
MY
Kim
Heounjeong
H
Go
Jaemoon
J
Koh
Kyoungbun
K
Lee
Hye-Sook
HS
Min
Min-A
MA
Kim
Yoon Kyung
YK
Jeon
Hye-Seung
HS
Lee
Kyung-Chul
KC
Moon
So Yeon
SY
Park
Woo-Ho
WH
Kim
Doo Hyun
DH
Chung
D000230:Adenocarcinoma / Q000473:pathology*; D016282:Aspartic Acid Endopeptidases / Q000032:analysis / Q000096:biosynthesis*; D014408:Biomarkers, Tumor / Q000032:analysis*; D004268:DNA-Binding Proteins / Q000032:analysis / Q000096:biosynthesis; D006801:Humans; D007150:Immunohistochemistry; D008175:Lung Neoplasms / Q000473:pathology*; D009362:Neoplasm Metastasis / Q000473:pathology; D046888:Tissue Array Analysis; D014157:Transcription Factors
D014408:Biomarkers, Tumor; D004268:DNA-Binding Proteins; C504003:TTF1 protein, human; D014157:Transcription Factors; D016282:Aspartic Acid Endopeptidases; C498549:NAPSA protein, human
immunohistochemistry; metastasis; napsin A; origin of adenocarcinoma; pulmonary adenocarcinoma