Frequency of EGFR and KRAS mutations in Japanese patients with lung adenocarcinoma with features of the mucinous subtype of bronchioloalveolar carcinoma.
BACKGROUND
Adenocarcinoma of the lung, especially bronchioloalveolar carcinoma (BAC) and adenocarcinoma with BAC features (AWBF), is potentially sensitive to epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs); however, the efficacy seems to differ between the histologic subtypes. Mucinous BAC and AWBF (MBAC/AWBF) are not particularly responsive to EGFR-TKIs compared with nonmucinous BAC/AWBF (N-MBAC/AWBF). This may be due to the rarity of EGFR mutations and high frequency of KRAS mutations in MBAC/AWBF in contrast to N-MBAC/AWBF.


METHODS
One hundred ninety-one patients with adenocarcinoma of the lung underwent surgery at our institution. There were 59 patients (30%) diagnosed with BAC/AWBF; 20 had MBAC/AWBF (10%) and 39 had N-MBAC/AWBF (20%). We isolated 44 tissue specimens from these patients (20 consecutive cases of MBAC/AWBFs and 24 randomly chosen cases of N-MBAC/AWBFs as the control group), and we analyzed them for EGFR and KRAS mutations. We used the peptide nucleic acid-locked nucleic acid polymerase chain reaction clump method to detect EGFR mutations and conventional DNA sequencing to identify KRAS mutations.


RESULTS
EGFR mutations were found in three of the 20 MBAC/AWBFs (15%) and in 14 of the 24 N-MBAC/AWBFs (58%) (p = 0.005). In addition, there were 14 KRAS mutations identified in the 20 MBAC/AWBFs (70%) and seven in the 24 N-MBAC/AWBFs (29%) (p = 0.0144).


CONCLUSIONS
The incidence of EGFR mutation is low and that of KRAS mutation is frequent in MBAC/AWBFs. Conversely, the incidence of EGFR mutation is high and KRAS mutation is low in N-MBAC/AWBFs. Based on these findings, EGFR-TKIs may not be effective in patients with MBAC/AWBF.
Hata
Akito
A
Division of Integrated Oncology, Institute of Biomedical Research and Innovation, Chuo-ku, Kobe, Japan.
Katakami
Nobuyuki
N
Fujita
Shiro
S
Kaji
Reiko
R
Imai
Yukihiro
Y
Takahashi
Yutaka
Y
Nishimura
Takashi
T
Tomii
Keisuke
K
Ishihara
Kyosuke
K
D000230:Adenocarcinoma / Q000188:drug therapy / Q000235:genetics / Q000601:surgery; D002282:Adenocarcinoma, Bronchiolo-Alveolar / Q000188:drug therapy / Q000235:genetics* / Q000601:surgery; D002288:Adenocarcinoma, Mucinous / Q000188:drug therapy / Q000235:genetics* / Q000601:surgery; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002289:Carcinoma, Non-Small-Cell Lung / Q000188:drug therapy / Q000235:genetics* / Q000601:surgery; D003131:Combined Modality Therapy; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000235:genetics*; D005260:Female; D000077156:Gefitinib; D006801:Humans; D015994:Incidence; D008175:Lung Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D016133:Polymerase Chain Reaction; D047428:Protein Kinase Inhibitors / Q000627:therapeutic use; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016283:Proto-Oncogene Proteins p21(ras); D011799:Quinazolines / Q000627:therapeutic use; D015996:Survival Rate; D016896:Treatment Outcome; D018631:ras Proteins / Q000235:genetics*
C117307:KRAS protein, human; D047428:Protein Kinase Inhibitors; D011518:Proto-Oncogene Proteins; D011799:Quinazolines; C512478:EGFR protein, human; D066246:ErbB Receptors; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins; D000077156:Gefitinib