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Exon 8 amplification of epidermal growth factor receptor ( EGFR ) in invasive breast carcinomas
Author(s) -
Souka Efthimia,
Alexiadis Evaggelos,
Theohari Irini,
Giannopoulou Ioanna,
Papadimitriou Christos,
Nakopoulou Lydia
Publication year - 2012
Publication title -
histopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.626
H-Index - 124
eISSN - 1365-2559
pISSN - 0309-0167
DOI - 10.1111/j.1365-2559.2012.04315.x
Subject(s) - epidermal growth factor receptor , exon , biology , immunohistochemistry , breast cancer , cancer research , intron , gene duplication , microbiology and biotechnology , copy number variation , univariate analysis , pathology , gene , cancer , medicine , multivariate analysis , genetics , immunology , genome
Souka E, Alexiadis E, Theohari I, Giannopoulou I, Papadimitriou C & Nakopoulou L
(2012) Histopathology 61, 644–651 Exon 8 amplification of epidermal growth factor receptor ( EGFR ) in invasive breast carcinomas Aims: The rate of EGFR amplification in breast cancer ranges between 0% and 15%. Recent studies have focused on the amplification status of cytosine–adenine (CA) repeats in intron 1 of the gene and correlated it with increased EGFR protein. The aim of this study was to investigate, for the first time, the significance of coding exon 8 amplification of EGFR in invasive breast cancer. Methods and results: We investigated, by means of real‐time polymerase chain reaction (PCR), the amplification status of exon 8 of the EGFR gene in 148 paraffin‐embedded tissue sections, 115 with invasive breast carcinoma and 33 controls. Immunohistochemistry was utilized to detect EGFR and human epidermal growth factor receptor 2 (HER2) expression. Univariate and multivariate statistical analyses were performed for the evaluation of our results. EGFR amplification was observed in 7.8% of the patients, and EGFR was immunodetected in 9.6%. EGFR amplification was correlated positively with EGFR expression ( P < 0.0001), HER2 expression ( P = 0.023), coexpression of EGFR/HER2 ( P < 0.0001) and nuclear grade ( P = 0.047), and inversely with ER protein expression ( P = 0.047). Conclusions: It appears that amplification of the coding sequence exon 8 exhibits similar biological behaviour to amplification of the regulatory sequence in intron 1, leading to elevated levels of EGFR protein.