title: Identification of Predictive Markers for Response to Neoadjuvant Chemoradiation in Rectal Carcinomas by Proteomic Isotope Coded Protein Label (ICPL) Analysis.
abstract: Neoadjuvant chemoradiation (nCRT) is an established procedure in stage union internationale contre le cancer (UICC) II/III rectal carcinomas. Around 53% of the tumours present with good tumor regression after nCRT, and 8%-15% are complete responders. Reliable selection markers would allow the identification of poor or non-responders prior to therapy. Tumor biopsies were harvested from 20 patients with rectal carcinomas, and stored in liquid nitrogen prior to therapy after obtaining patients' informed consent (Erlangen-No.3784). Patients received standardized nCRT with 5-Fluoruracil (nCRT I) or 5-Fluoruracil ± Oxaliplatin (nCRT II) according to the CAO/ARO/AIO-04 protocol. After surgery, regression grading (Dworak) of the tumors was performed during histopathological examination of the specimens. Tumors were classified as poor (Dworak 1 + 2) or good (Dworak 3 + 4) responders. Laser capture microdissection (LCM) for tumor enrichment was performed on preoperative biopsies. Differences in expressed proteins between poor and good responders to nCRT I and II were identified by proteomic analysis (Isotope Coded Protein Label, ICPL™) and selected markers were validated by immunohistochemistry. Tumors of 10 patients were classified as histopathologically poor (Dworak 1 or 2) and the other 10 tumor samples as histopathologically good (Dworak 3 or 4) responders to nCRT after surgery. Sufficient material in good quality was harvested for ICPL analysis by LCM from all biopsies. We identified 140 differentially regulated proteins regarding the selection criteria and the response to nCRT. Fourteen of these proteins were synchronously up-regulated at least 1.5-fold after nCRT I or nCRT II (e.g., FLNB, TKT, PKM2, SERINB1, IGHG2). Thirty-five proteins showed a complete reciprocal regulation (up or down) after nCRT I or nCRT II and the rest was regulated either according to nCRT I or II. The protein expression of regulated proteins such as PLEC1, TKT, HADHA and TAGLN was validated successfully by immunohistochemistry. ICPL is a valid method to identify differentially expressed proteins in rectal carcinoma tissue between poor vs. good responders to nCRT. The identified protein markers may act as selection criteria for nCRT in the future, but our preliminary findings must be reproduced and validated in a prospective cohort.
authors: Department of Surgery, University Hospital Erlangen, Erlangen 91054, Germany. roland.croner@uk-erlangen.de.
authors: Roland S
authors: RS
authors: Croner
authors: Max-Planck-Institute of Biochemistry, Martinsried 82152, Germany. sevim@gmx.net.
authors: Müzeyyen
authors: M
authors: Sevim
authors: School of Biological Sciences/Proteomics Unit, University of Essex; Wivenhoe Park, Colchester, Essex CO4 3SQ, UK. mmetod@essex.ac.uk.
authors: Metodi V
authors: MV
authors: Metodiev
authors: Department of Surgery, University Hospital Göttingen, Göttingen 37075, Germany. jo.peter@chirurgie-goettingen.de.
authors: Peter
authors: P
authors: Jo
authors: Department of Surgery, University Hospital Göttingen, Göttingen 37075, Germany. mghadimi@chirurgie-goettingen.de.
authors: Michael
authors: M
authors: Ghadimi
authors: Department of Surgery, University Hospital Erlangen, Erlangen 91054, Germany. vera.schellerer@uk-erlangen.de.
authors: Vera
authors: V
authors: Schellerer
authors: Department of Surgery, University Hospital Erlangen, Erlangen 91054, Germany. maximilian.brunner@uk-erlangen.de.
authors: Maximillian
authors: M
authors: Brunner
authors: Department of Pathology, University Hospital Erlangen, Erlangen 91054, Germany. carol.geppert@uk-erlangen.de.
authors: Carol
authors: C
authors: Geppert
authors: Department of Pathology, University Hospital Erlangen, Erlangen 91054, Germany. tilman.rau@pathology.unibe.ch.
authors: Tilman
authors: T
authors: Rau
authors: Division of Molecular and Experimental Surgery, University Hospital Erlangen, Erlangen 91054, Germany. michael.stuerzl@uk-erlangen.de.
authors: Michael
authors: M
authors: Stürzl
authors: Division of Molecular and Experimental Surgery, University Hospital Erlangen, Erlangen 91054, Germany. elisabeth.naschberger@uk-erlangen.de.
authors: Elisabeth
authors: E
authors: Naschberger
authors: Department of Surgery, University Hospital Erlangen, Erlangen 91054, Germany. klaus.matzel@uk-erlangen.de.
authors: Klaus E
authors: KE
authors: Matzel
authors: Department of Surgery, University Hospital Erlangen, Erlangen 91054, Germany. werner.hohenberger@uk-erlangen.de.
authors: Werner
authors: W
authors: Hohenberger
authors: Max-Planck-Institute of Biochemistry, Martinsried 82152, Germany. lottspei@biochem.mpg.de.
authors: Friedrich
authors: F
authors: Lottspeich
authors: Max-Planck-Institute of Biochemistry, Martinsried 82152, Germany. kellerma@biochem.mpg.de.
authors: Josef
authors: J
authors: Kellermann
mesh_terms: D015415:Biomarkers; D001706:Biopsy; D059248:Chemoradiotherapy; D006801:Humans; D007150:Immunohistochemistry; D020360:Neoadjuvant Therapy; D011379:Prognosis; D020543:Proteome; D040901:Proteomics / Q000379:methods; D012004:Rectal Neoplasms / Q000175:diagnosis / Q000378:metabolism* / Q000401:mortality* / Q000628:therapy; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; D020543:Proteome
keywords: ICPL; chemoradiation; proteomic; rectal cancer