title: Expression and mutation analysis of the discoidin domain receptors 1 and 2 in non-small cell lung carcinoma.
abstract: The discoidin domain receptors, (DDR)1 and DDR2, have been linked to numerous human cancers. We sought to determine expression levels of DDRs in human lung cancer, investigate prognostic determinates, and determine the prevalence of recently reported mutations in these receptor tyrosine kinases. Tumour samples from 146 non-small cell lung carcinoma (NSCLC) patients were analysed for relative expression of DDR1 and DDR2 using quantitative real-time PCR (qRT-PCR). An additional 23 matched tumour and normal tissues were tested for differential expression of DDR1 and DDR2, and previously reported somatic mutations. Discoidin domain receptor 1 was found to be significantly upregulated by 2.15-fold (P=0.0005) and DDR2 significantly downregulated to an equivalent extent (P=0.0001) in tumour vs normal lung tissue. Discoidin domain receptor 2 expression was not predictive for patient survival; however, DDR1 expression was significantly associated with overall (hazard ratio (HR) 0.43, 95% CI=0.22-0.83, P=0.014) and disease-free survival (HR=0.56, 95% CI=0.33-0.94, P=0.029). Multivariate analysis revealed DDR1 is an independent favourable predictor for prognosis independent of tumour differentiation, stage, histology, and patient age. However, contrary to previous work, we did not observe DDR mutations. We conclude that whereas altered expression of DDRs may contribute to malignant progression of NSCLC, it is unlikely that this results from mutations in the DDR1 and DDR2 genes that we investigated.
authors.affiliation: Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada.
authors.forename: C E
authors.initials: CE
authors.lastname: Ford
authors.forename: S K
authors.initials: SK
authors.lastname: Lau
authors.forename: C Q
authors.initials: CQ
authors.lastname: Zhu
authors.forename: T
authors.initials: T
authors.lastname: Andersson
authors.forename: M S
authors.initials: MS
authors.lastname: Tsao
authors.forename: W F
authors.initials: WF
authors.lastname: Vogel
mesh_terms: D000818:Animals; D014408:Biomarkers, Tumor / Q000032:analysis*; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D004252:DNA Mutational Analysis; D000070818:Discoidin Domain Receptors; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D009154:Mutation; D011110:Polymorphism, Genetic; D011379:Prognosis; D020794:Receptor Protein-Tyrosine Kinases / Q000096:biosynthesis* / Q000235:genetics; D011975:Receptors, Mitogen / Q000096:biosynthesis* / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D014408:Biomarkers, Tumor; D011975:Receptors, Mitogen; D000070818:Discoidin Domain Receptors; D020794:Receptor Protein-Tyrosine Kinases