title: Diagnostic utility of S100A1 expression in renal cell neoplasms: an immunohistochemical and quantitative RT-PCR study.
abstract: S100A1 is a calcium-binding protein, which has been recently found in renal cell neoplasms. We evaluated the diagnostic utility of immunohistochemical detection of S100A1 in 164 renal cell neoplasms. Forty-one clear cell, 32 papillary, and 51 chromophobe renal cell carcinomas, and 40 oncocytomas, 164 samples of normal renal parenchyma adjacent to the tumors and 13 fetal kidneys were analyzed. The levels of S100A1 mRNA detected by quantitative RT-PCR analysis of frozen tissues from seven clear cell, five papillary, and six chromophobe renal cell carcinomas, four oncocytomas, and nine samples of normal renal tissues adjacent to neoplasms were compared with the immunohistochemical detection of protein expression. Clear cell and papillary renal cell carcinomas showed positive reactions for S100A1 in 30 out of 41 tumors (73%) and in 30 out of 32 (94%) tumors, respectively. Thirty-seven renal oncocytomas out of 40 (93%) were positive for S100A1, whereas 48 of 51 (94%) chromophobe renal cell carcinomas were negative. S100A1 protein was detected in all samples of unaffected and fetal kidneys. S100A1 mRNA was detected by RT-PCR in all normal kidneys and renal cell neoplasms, although at very different levels. Statistical analyses comparing the different expression of S100A1 in clear cell and chromophobe renal cell carcinomas observed by immunohistochemical and RT-PCR methods showed significant values (P<0.001), such as when comparing by both techniques the different levels of S100A1 expression in chromophobe renal cell carcinomas and oncocytomas (P<0.001). Our study shows that S100A1 protein is expressed in oncocytomas, clear cell and papillary renal cell carcinomas but not in chromophobe renal cell carcinomas. Its immunodetection is potentially useful for the differential diagnosis between chromophobe renal cell carcinoma and oncocytoma. Further, S100A1 protein expression is constantly detected in the normal parenchyma of the adult and fetal kidney.
authors.affiliation: Department of Pathology, University of Sassari, Sassari, Italy.
authors.forename: Paolo Cossu
authors.initials: PC
authors.lastname: Rocca
authors.forename: Matteo
authors.initials: M
authors.lastname: Brunelli
authors.forename: Stefano
authors.initials: S
authors.lastname: Gobbo
authors.forename: Albino
authors.initials: A
authors.lastname: Eccher
authors.forename: Emma
authors.initials: E
authors.lastname: Bragantini
authors.forename: Maria M
authors.initials: MM
authors.lastname: Mina
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Ficarra
authors.forename: Filiberto
authors.initials: F
authors.lastname: Zattoni
authors.forename: Alberto
authors.initials: A
authors.lastname: Zamò
authors.forename: Maurizio
authors.initials: M
authors.lastname: Pea
authors.forename: Aldo
authors.initials: A
authors.lastname: Scarpa
authors.forename: Marco
authors.initials: M
authors.lastname: Chilosi
authors.forename: Fabio
authors.initials: F
authors.lastname: Menestrina
authors.forename: Franco
authors.initials: F
authors.lastname: Bonetti
authors.forename: John N
authors.initials: JN
authors.lastname: Eble
authors.forename: Guido
authors.initials: G
authors.lastname: Martignoni
mesh_terms: D018249:Adenoma, Oxyphilic / Q000175:diagnosis / Q000235:genetics / Q000378:metabolism; D002292:Carcinoma, Renal Cell / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D003937:Diagnosis, Differential; D006801:Humans; D007150:Immunohistochemistry; D007668:Kidney / Q000737:chemistry / Q000378:metabolism / Q000473:pathology; D007680:Kidney Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D009418:S100 Proteins / Q000235:genetics* / Q000378:metabolism; D012680:Sensitivity and Specificity
chemical_list: D012333:RNA, Messenger; D009418:S100 Proteins; C110294:S100A1 protein