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Open Access Research article

Germ-line mutations in epidermal growth factor receptor (EGFR) are rare but may contribute to oncogenesis: A novel germ-line mutation in EGFR detected in a patient with lung adenocarcinoma

Irene Centeno1, Pilar Blay2, Iñigo Santamaría1, Aurora Astudillo34, Ana S Pitiot1, Fernando G Osorio5, Patricia González-Arriaga6, Fernando Iglesias14, Primitiva Menéndez3, Adonina Tardón6, Jose M Freije5 and Milagros Balbín1*

Author Affiliations

1 Laboratorio de Oncología Molecular, Instituto Universitario de Oncología del Principado de Asturias, Hospital Universitario Central de Asturias, (Celestino Villamil s/n), Oviedo, (33006), Spain

2 Unidad de Cáncer Familiar, Servicio de Oncología Médica, Instituto Universitario de Oncología del Principado de Asturias, Hospital Universitario Central de Asturias, (Celestino Villamil s/n), Oviedo, (33006), Spain

3 Servicio de Anatomía Patológica, Hospital Universitario Central de Asturias, (Celestino Villamil s/n), Oviedo, (33006), Spain

4 Banco de Tumores, Instituto Universitario de Oncología del Principado de Asturias, Hospital Universitario Central de Asturias. (Celestino Villamil s/n), Oviedo, (33006), Spain

5 Departamento de Bioquímica y Biología Molecular, Instituto Universitario de Oncología del Principado de Asturias, Universidad de Oviedo, (Campus del Cristo), Oviedo, (33006), Spain

6 Unidad de Epidemiología Molecular, Instituto Universitario de Oncología del Principado de Asturias, Facultad de Medicina, Universidad de Oviedo, (Campus del Cristo), Oviedo, (33006), Spain

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BMC Cancer 2011, 11:172  doi:10.1186/1471-2407-11-172

Published: 16 May 2011

Abstract

Background

A subset of lung cancer patients harbour EGFR somatic mutations in their tumours and are candidates for treatment with EGFR tyrosine kinase inhibitors. In a few cases EGFR mutations have also been found in the germ line, suggesting a role in lung carcinogenesis. Objetives of this study were: 1) To analyze the EGFR gene mutations in a population diagnosed with lung adenocarcinoma from Northern Spain. 2) To determine the frequency of a new germ-line mutation found in our laboratory as well as the frequency in our population of three other EGFR germ-line mutations detected by other authors. 3) To determine whether the novel mutation detected may have a functional effect on the EGFR protein.

Methods

Tumour DNA samples were obtained from frozen or paraffin embedded tumour tissues. Samples of DNA from peripheral blood cells were obtained from 912 individuals with lung cancer recruited from the CAPUA study [1,2], 477 unrelated healthy donor individuals and 32 individuals with other types of cancer. EGFR gene exons 18 to 21 were studied by direct standard dideoxy sequencing. Specific mutations were determined either by direct sequencing or by specific RFLP analysis. Cell lines were transfected with EGFR-mutant plasmids and analysed by western blot with antibodies specific for total or phosphorylated-EGFR.

Results

We found EGFR mutation in 12 of the 71 tumour samples (17%). One tumour contained two mutations. One mutation (p.R776G) was present as a germ line. Using an RFLP analysis, this mutation was not found in 954 alleles from healthy individuals studied, concluding that it is not a polymorphism. The mutation was not found either in genomic DNA from 912 lung cancer patients. Three additional EGFR germ-line mutations that were already described were not found in any of the studied samples. These observations show that EGFR mutated alleles are rare in the population. In vitro studies revealed that tyrosine autophosphorylation is enhanced in p.R776G-mutant EGFR when compared with wild-type EGFR. This enhanced autophosphorylation in the absence of ligand may be associated with a proliferative advantage.

Conclusions

Germ-line mutations in EGFR are rare but may contribute to oncogenesis