Epidermal growth factor receptor structural alterations in gastric cancer.
BACKGROUND
EGFR overexpression has been described in many human tumours including gastric cancer. In NSCLC patients somatic EGFR mutations, within the kinase domain of the protein, as well as gene amplification were associated with a good clinical response to EGFR inhibitors. In gastric tumours data concerning structural alterations of EGFR remains controversial. Given its possible therapeutic relevance, we aimed to determine the frequency and type of structural alterations of the EGFR gene in a series of primary gastric carcinomas.


METHODS
Direct sequencing of the kinase domain of the EGFR gene was performed in a series of 77 primary gastric carcinomas. FISH analysis was performed in 30 cases. Association studies between EGFR alterations and the clinical pathological features of the tumours were performed.


RESULTS
Within the 77 primary gastric carcinomas we found two EGFR somatic mutations and several EGFR polymorphisms in exon 20. Six different intronic sequence variants of EGFR were also found. Four gastric carcinomas showed balanced polysomy or EGFR gene amplification. We verified that gastric carcinoma with alterations of EGFR (somatic mutations or copy number variation) showed a significant increase of tumour size (p = 0.0094) in comparison to wild-type EGFR carcinomas.


CONCLUSIONS
We demonstrate that EGFR structural alterations are rare in gastric carcinoma, but whenever present, it leads to tumour growth. We considered that searching for EGFR alterations in gastric cancer is likely to be clinically important in order to identify patients susceptible to respond to tyrosine kinase inhibitors.
Moutinho
Cátia
C
Instituto de Patologia e Imunologia Molecular da Universidade do Porto (IPATIMUP), 4200-465 Porto, Portugal. catiamoutinhos@hotmail.com
Mateus
Ana R
AR
Milanezi
Fernanda
F
Carneiro
Fátima
F
Seruca
Raquel
R
Suriano
Gianpaolo
G
D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use; D002277:Carcinoma / Q000188:drug therapy / Q000201:enzymology / Q000235:genetics* / Q000473:pathology; D004252:DNA Mutational Analysis; D066246:ErbB Receptors / Q000235:genetics* / Q000378:metabolism; D005091:Exons; D005260:Female; D005784:Gene Amplification; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007438:Introns; D008297:Male; D008875:Middle Aged; D009154:Mutation; D018579:Patient Selection; D011110:Polymorphism, Genetic; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use; D013274:Stomach Neoplasms / Q000188:drug therapy / Q000201:enzymology / Q000235:genetics* / Q000473:pathology
D000970:Antineoplastic Agents; D047428:Protein Kinase Inhibitors; C512478:EGFR protein, human; D066246:ErbB Receptors