title: RT-PCR versus immunohistochemistry for correlation and quantification of ERCC1, BRCA1, TUBB3 and RRM1 in NSCLC.
abstract: BACKGROUND
  Customized chemotherapy is increasingly used in the management of patients with advanced non-small cell lung cancer (NSCLC). However, the most reliable methodology to determine biomarker status is neither fully elucidated nor agreed upon. Accordingly, we evaluated the predictive efficiency of qRT-PCR and immunohistochemical analysis (IHC) on excision cross complementation group 1 (ERCC1), breast cancer susceptibility gene 1 (BRCA1), ribonucleotide reductase subunit M1 (RRM1) and class III β-tubulin (TUBB3).
  
  
  METHODS
  IHC and qRT-PCR on ERCC1, BRCA1, RRM1 and TUBB3 were performed on surgically resected tissue samples from NSCLC-patients included in a randomized trial. The median values of the biomarker expression dichotomized the population and were correlated to clinical endpoints.
  
  
  RESULTS
  Representative tissue samples from 33 patients showed no significant correlations between mRNA and protein expression. Predictive impact was demonstrated for all four biomarkers, when assessed by IHC, and reached significance for overall survival in patients with ERCC1-negative (14.3 vs. 8.5 months, p=0.018) and TUBB3-negative (18.5 vs. 11.10, p=0.027) tumours, while this was not the case for qRT-PCR.
  
  
  CONCLUSIONS
  IHC discriminated more effectively than qRT-PCR across four NSCLC-relevant biomarkers. The findings are further supported by the demonstrated lack of correlation between transcript and protein.
authors: Department of Oncology, Finsen Centre, National University Hospital, Copenhagen, Denmark. adamvilmar@hotmail.com
authors: A
authors: A
authors: Vilmar
authors: J
authors: J
authors: Garcia-Foncillas
authors: M
authors: M
authors: Huarriz
authors: E
authors: E
authors: Santoni-Rugiu
authors: J B
authors: JB
authors: Sorensen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D019313:BRCA1 Protein / Q000235:genetics* / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000032:analysis / Q000235:genetics; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy / Q000235:genetics / Q000473:pathology*; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D018572:Disease-Free Survival; D004720:Endonucleases / Q000235:genetics* / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D008175:Lung Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000473:pathology*; D008875:Middle Aged; D011237:Predictive Value of Tests; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods*; D012262:Ribonucleoside Diphosphate Reductase; D014404:Tubulin / Q000235:genetics* / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000235:genetics* / Q000378:metabolism; D055815:Young Adult
chemical_list: D019313:BRCA1 Protein; D014408:Biomarkers, Tumor; D004268:DNA-Binding Proteins; C498585:TUBB3 protein, human; D014404:Tubulin; D025521:Tumor Suppressor Proteins; C475286:RRM1 protein, human; D012262:Ribonucleoside Diphosphate Reductase; C071447:ERCC1 protein, human; D004720:Endonucleases