Use of cigarette-smoking history to estimate the likelihood of mutations in epidermal growth factor receptor gene exons 19 and 21 in lung adenocarcinomas.
OBJECTIVE
Lung adenocarcinomas with mutations in exons 19 and 21 of the epidermal growth factor receptor gene (EGFR) demonstrate sensitivity to gefitinib or erlotinib. Investigators have reported an association between EGFR mutations and the amount and duration of cigarette smoking, with the highest incidence of mutations seen in never smokers.


METHODS
EGFR exon 19 and 21 mutation status was determined in 265 tumor samples using direct sequencing, polymerase chain reaction (PCR), or PCR-based restriction fragment length polymorphism analysis. A detailed smoking history was obtained. Patients were categorized as never smokers (< 100 lifetime cigarettes), former smokers (quit > or = 1 year ago), or current smokers (quit < 1 year ago).


RESULTS
We detected EGFR mutations in 34 (51%) of 67 never smokers (95% CI, 38% to 64%), 29 (19%) of 151 former smokers (95% CI, 13% to 27%), and two (4%) of 47 current smokers (95% CI, 1% to 16%). Significantly fewer EGFR mutations were found in people who smoked for more than 15 pack-years (P < .001) or stopped smoking less than 25 years ago (P < .02) compared with individuals who never smoked. The number of smoking pack-years and smoke-free years predicted the prevalence of EGFR mutations (areas under receiver operating characteristic curve = 0.78 and 0.77, respectively).


CONCLUSIONS
The likelihood of EGFR mutations in exons 19 and 21 decreases as the number of pack-years increases. Mutations were less common in people who smoked for more than 15 pack-years or who stopped smoking cigarettes less than 25 years ago. These data can assist clinicians in assessing the likelihood of exon 19 and 21 EGFR mutations in patients with lung adenocarcinoma when mutational analysis is not feasible.
Pham
DuyKhanh
D
Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
Kris
Mark G
MG
Riely
Gregory J
GJ
Sarkaria
Inderpal S
IS
McDonough
Tiffani
T
Chuai
Shaokun
S
Venkatraman
Ennapadam S
ES
Miller
Vincent A
VA
Ladanyi
Marc
M
Pao
William
W
Wilson
Richard K
RK
Singh
Bhuvanesh
B
Rusch
Valerie W
VW
D000230:Adenocarcinoma / Q000188:drug therapy / Q000235:genetics*; D000069347:Erlotinib Hydrochloride; D005091:Exons; D005260:Female; D000077156:Gefitinib; D018773:Genes, erbB-1 / Q000187:drug effects / Q000235:genetics*; D006801:Humans; D015994:Incidence; D008175:Lung Neoplasms / Q000188:drug therapy / Q000235:genetics*; D008297:Male; D008967:Molecular Biology; D009154:Mutation; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use; D011799:Quinazolines / Q000627:therapeutic use; D012372:ROC Curve; D012907:Smoking
D047428:Protein Kinase Inhibitors; D011799:Quinazolines; D000069347:Erlotinib Hydrochloride; D000077156:Gefitinib