title: Diagnostic and prognostic role of immunohistochemical expression of napsin-A aspartic peptidase in clear cell and papillary renal cell carcinoma: a study including 233 primary and metastatic cases.
abstract: Napsin-A aspartic peptidase (napsin-A) is an aspartic protease that is predominantly expressed in the proximal renal tubules and type II pneumocytes of the lung. Recently, napsin-A was reported to be present in a proportion of renal cell carcinomas (RCCs). However, the utilization of napsin-A immunohistochemistry as a routine diagnostic tool for RCC, and the correlation of the level of napsin-A expression with histologic features have not yet been established. In the current study, using tissue microarrays composed of primary and metastatic RCCs, napsin-A expression was demonstrated in 86 of 222 (39%) clear cell RCCs (CRCCs) and 16 of 21 (76%) papillary RCCs (PRCCs), with a strong and diffuse staining pattern observed in PRCCs and a relatively weak and focal positivity in CRCCs. Compared with primary CRCCs, a comparable proportion of metastatic CRCCs retained napsin-A expression (45/132, 34%), suggesting the potential utility of napsin-A in the evaluation of metastatic tumors. The expression of napsin-A was also found to be inversely correlated to aggressive local tumor characteristics, such as advanced pathologic stage and high Fuhrman nuclear grade. We conclude that napsin-A may be a valuable immunohistochemical marker in the diagnosis of RCCs, particularly PRCC.
authors.affiliation: Departments of *Pathology †Urology, McGill University Health Center, Montreal, QC, Canada ‡Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX.
authors.forename: Bin
authors.initials: B
authors.lastname: Xu
authors.forename: Samuel
authors.initials: S
authors.lastname: Abourbih
authors.forename: Kanishka
authors.initials: K
authors.lastname: Sircar
authors.forename: Wassim
authors.initials: W
authors.lastname: Kassouf
authors.forename: Armen
authors.initials: A
authors.lastname: Aprikian
authors.forename: Simon
authors.initials: S
authors.lastname: Tanguay
authors.forename: Fadi
authors.initials: F
authors.lastname: Brimo
mesh_terms: D018262:Adenocarcinoma, Clear Cell / Q000175:diagnosis*; D016282:Aspartic Acid Endopeptidases / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000378:metabolism*; D063646:Carcinogenesis; D002292:Carcinoma, Renal Cell / Q000175:diagnosis*; D003955:Diagnostic Tests, Routine; D006801:Humans; D007680:Kidney Neoplasms / Q000175:diagnosis*; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D011379:Prognosis; D046888:Tissue Array Analysis
chemical_list: D014408:Biomarkers, Tumor; D016282:Aspartic Acid Endopeptidases; C498549:NAPSA protein, human