Lung adenocarcinoma with EGFR amplification has distinct clinicopathologic and molecular features in never-smokers.
In a subset of lung adenocarcinomas, the epidermal growth factor receptor (EGFR) is activated by kinase domain mutations and/or gene amplification, but the interaction between the two types of abnormalities is complex and unclear. For this study, we selected 99 consecutive never-smoking women of East Asian origin with lung adenocarcinomas that were characterized by histologic subtype. We analyzed EGFR mutations by PCR-capillary sequencing, EGFR copy number abnormalities by fluorescence and chromogenic in situ hybridization and quantitative PCR, and EGFR expression by immunohistochemistry with both specific antibodies against exon 19 deletion-mutated EGFR and total EGFR. We compared molecular and clinicopathologic features with disease-free survival. Lung adenocarcinomas with EGFR amplification had significantly more EGFR exon 19 deletion mutations than adenocarcinomas with disomy, and low and high polysomy (100% versus 54%, P = 0.009). EGFR amplification occurred invariably on the mutated and not the wild-type allele (median mutated/wild-type ratios 14.0 versus 0.33, P = 0.003), was associated with solid histology (P = 0.008), and advanced clinical stage (P = 0.009). EGFR amplification was focally distributed in lung cancer specimens, mostly in regions with solid histology. Patients with EGFR amplification had a significantly worse outcome in univariate analysis (median disease-free survival, 16 versus 31 months, P = 0.01) and when adjusted for stage (P = 0.027). Lung adenocarcinomas with EGFR amplification have a unique association with exon 19 deletion mutations and show distinct clinicopathologic features associated with a significantly worsened prognosis. In these cases, EGFR amplification is heterogeneously distributed, mostly in areas with a solid histology.
Sholl
Lynette M
LM
Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
Yeap
Beow Y
BY
Iafrate
A John
AJ
Holmes-Tisch
Alison J
AJ
Chou
Yi-Ping
YP
Wu
Ming-Tsang
MT
Goan
Yih-Gang
YG
Su
Li
L
Benedettini
Elisa
E
Yu
Jian
J
Loda
Massimo
M
Jänne
Pasi A
PA
Christiani
David C
DC
Chirieac
Lucian R
LR
D000230:Adenocarcinoma / Q000235:genetics* / Q000473:pathology; D002282:Adenocarcinoma, Bronchiolo-Alveolar / Q000235:genetics / Q000473:pathology; D000328:Adult; D000368:Aged; D002291:Carcinoma, Papillary / Q000235:genetics / Q000473:pathology; D066246:ErbB Receptors / Q000235:genetics*; D005260:Female; D005784:Gene Amplification; D018628:Gene Dosage; D006801:Humans; D007124:Immunoenzyme Techniques; D017404:In Situ Hybridization, Fluorescence; D008175:Lung Neoplasms / Q000235:genetics* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D011379:Prognosis; D011518:Proto-Oncogene Proteins / Q000235:genetics; D016283:Proto-Oncogene Proteins p21(ras); D012907:Smoking / Q000235:genetics*; D015996:Survival Rate; D018631:ras Proteins / Q000235:genetics
C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; C512478:EGFR protein, human; D066246:ErbB Receptors; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins