title: Determining the profiles and parameters for gene amplification testing of growth factor receptors in lung cancer.
abstract: Growth factor receptors (GFRs) are amenable to therapeutic intervention in cancer and it is important to select patients appropriately. One of the mechanisms for activation of GFRs is gene amplification (GA) but discrepancies arising from the difficulties associated with data interpretation and the lack of agreed parameters confound the comparison of results from different laboratories. Here, we attempt to establish appropriate conditions for standardization of the determination of GA in a panel of GFRs. A NSCLC tissue microarray panel containing 302 samples was screened for alterations at ALK, FGFR1, FGFR2, FGFR3, ERBB2, IGF1R, KIT, MET and PDGFRA by FISH, immunostaining and/or real-time quantitative RT-PCR. Strong amplification was found for FGFR1, ERBB2, KIT/PDFGRA and MET, with frequencies ranging from 1 to 6%. Thresholds for overexpression and GA were established. Strong immunostaining was found in most tumors with ERBB2, MET and KIT amplification, although some tumors underwent strong immunostaining in the absence of GA. KIT and PDFGRA were always coamplified, but only one tumor showed PDGFRA overexpression, indicating that KIT is the main target. Amplification of FGFR1 predominated in squamous cell carcinomas, although the association with overexpression was inconclusive. Interestingly, alterations at ALK, MET, EGFR, ERBB2 and KRAS correlated with augmented levels of phospho-S6 protein, suggesting activation of the mTOR pathway, which may prove useful to pre-select tumors for testing. Overall, here, we provide with parameters for the determination of GA at ERBB2, MET, KIT and PDGFRA which could be implemented in the clinic to stratify lung cancer patients for specific treatments.
authors: Genes and Cancer Group, Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Hospitalet de Llobregat, Barcelona, Spain.
authors: Eva
authors: E
authors: Pros
authors: Sylvie
authors: S
authors: Lantuejoul
authors: Lydia
authors: L
authors: Sanchez-Verde
authors: Sandra D
authors: SD
authors: Castillo
authors: Ester
authors: E
authors: Bonastre
authors: Ana
authors: A
authors: Suarez-Gauthier
authors: Esther
authors: E
authors: Conde
authors: Juan C
authors: JC
authors: Cigudosa
authors: Fernando
authors: F
authors: Lopez-Rios
authors: Juan
authors: J
authors: Torres-Lanzas
authors: Josep
authors: J
authors: Castellví
authors: Santiago
authors: S
authors: Ramon y Cajal
authors: Elisabeth
authors: E
authors: Brambilla
authors: Montse
authors: M
authors: Sanchez-Cespedes
mesh_terms: D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics*; D005784:Gene Amplification; D020869:Gene Expression Profiling; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008175:Lung Neoplasms / Q000235:genetics*; D009154:Mutation; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D017978:Receptors, Growth Factor / Q000235:genetics* / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D017978:Receptors, Growth Factor