title: Proteomic identification of Reticulocalbin 1 as potential tumor marker in renal cell carcinoma.
abstract: Renal cell carcinoma (RCC) biomarkers are necessary for diagnosis and prognosis. They serve to monitor therapy response and follow-up, as drug targets, and therapy predictors in personalized treatments. Proteomics is a suitable method for biomarker discovery. Here we investigate differential protein expression in RCC, and we evaluate Reticulocalbin 1 (RCN1) use as a new potential marker. Neoplastic and healthy tissue samples were collected from 24 RCC patients during radical nephrectomy. Seven specimens were firstly processed by proteomic analysis (2-DE and MALDI-TOF) and 18 differentially expressed proteins from neoplastic and healthy renal tissues were identified. Among them, RCN1 was over-expressed in all cancer specimens analyzed by proteomics. Consequently RCN1 use as a potential marker was further evaluated in all 24 donors. RCN1 expression was verified by Western blotting (WB) and immunohistochemistry (IHC). WB analysis confirmed RCN1 over-expression in 21 out of 24 tumor specimens, whereas IHC displayed focal or diffuse expression of RCN1 in all 24 RCC tissues. Thus RCN1 appears as a potential marker for clinical approaches. A larger histopathological trial will clarify the prognostic value of RCN1 in RCC.
  
  
  CONCLUSIONS
  The present work aimed at finding new biomarkers for RCC - a life-threatening disease characterized by high incidence in Western countries - by performing differential proteomic analysis of neoplastic and normal renal tissues obtained from a small cohort of RCC patients. Some of the identified proteins have been previously associated to renal cancer however data confirming the possible use of these proteins in clinical practice are not available to date. By IHC we demonstrated that RCN1 could be easily employed in clinical practice, confirming RCN1 over-expression in RCC tissues of all examined patients, and weak protein expression in healthy renal tissues only in correspondence to the renal tubule section. These data indicate a promising role of RCN1 as a possible marker in RCC and indicate the proximal convoluted renal tubule as a putative origin point for RCC. Since IHC staining displayed different grades of intensity in tested tissues, we hypothesized that RCN1 could also be employed as a prognostic marker or as a response predictor for RCC-targeted therapy. To test such a hypothesis, a larger retrospective trial on paraffin-embedded tissues obtained from radical or partial nephrectomy of RCC patients is planned to be performed by our group.
authors.affiliation: Dipartimento di Oncologia, Università di Torino, Italy. Electronic address: giuliana.giribaldi@unito.it.
authors.forename: Giuliana
authors.initials: G
authors.lastname: Giribaldi
authors.forename: Giovanna
authors.initials: G
authors.lastname: Barbero
authors.forename: Giorgia
authors.initials: G
authors.lastname: Mandili
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Daniele
authors.forename: Amina
authors.initials: A
authors.lastname: Khadjavi
authors.forename: Agata
authors.initials: A
authors.lastname: Notarpietro
authors.forename: Daniela
authors.initials: D
authors.lastname: Ulliers
authors.forename: Mauro
authors.initials: M
authors.lastname: Prato
authors.forename: Valerio G
authors.initials: VG
authors.lastname: Minero
authors.forename: Antonino
authors.initials: A
authors.lastname: Battaglia
authors.forename: Marco
authors.initials: M
authors.lastname: Allasia
authors.forename: Andrea
authors.initials: A
authors.lastname: Bosio
authors.forename: Anna
authors.initials: A
authors.lastname: Sapino
authors.forename: Paolo
authors.initials: P
authors.lastname: Gontero
authors.forename: Bruno
authors.initials: B
authors.lastname: Frea
authors.forename: Dario
authors.initials: D
authors.lastname: Fontana
authors.forename: Paolo
authors.initials: P
authors.lastname: Destefanis
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002292:Carcinoma, Renal Cell / Q000175:diagnosis / Q000378:metabolism*; D005260:Female; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007680:Kidney Neoplasms / Q000175:diagnosis / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009392:Nephrectomy; D011379:Prognosis; D040901:Proteomics
chemical_list: D014408:Biomarkers, Tumor; D002135:Calcium-Binding Proteins; C078865:reticulocalbin
keywords: 3,3′-diaminobenzidine; DAB; IHC; Immunohistochemistry; Proteomics; RCC; RCN1; Renal cancer; Reticulocalbin 1; Tumor markers; WB; Western blotting; immunohistochemistry; renal cell carcinoma