Mechanisms of acquired resistance to EGFR-tyrosine kinase inhibitor in Korean patients with lung cancer

作者：Ji Wonjun; Choi Chang Min; Rho Jin Kyung; Jang Se Jin; Park Young Soo; Chun Sung Min; Kim Woo Sung; Lee Jung Shin; Kim Sang We; Lee Dae Ho; Lee Jae Cheol^*

来源：BMC Cancer, 2013, 13: 606.

DOI：10.1186/1471-2407-13-606

• Non-small cell lung carcinoma
• Epidermal growth factor receptor mutation
• EGFR tyrosine kinase inhibitor
• Acquired resistance
• Resistant mechanism
• Mass spectrometric genotyping

Background: Despite an initial good response to epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI), resistance to treatment eventually develops. Although several resistance mechanisms have been discovered, little data exist regarding Asian patient populations. %26lt;br%26gt;Methods: Among patients at a tertiary referral hospital in Korea who initially responded well to gefitinib and later acquired resistance to treatment, we selected those with enough tissues obtained before EGFR-TKI treatment and after the onset of resistance to examine mutations by mass spectrometric genotyping technology (Asan-Panel), MET amplification by fluorescence in situ hybridization (FISH), and analysis of AXL status, epithelial-to-mesenchymal transition (EMT) and neuroendocrine markers by immunohistochemistry. %26lt;br%26gt;Results: Twenty-six patients were enrolled, all of whom were diagnosed with adenocarcinoma with EGFR mutations (19del: 16, L858R: 10) except one (squamous cell carcinoma with 19del). Secondary T790M mutation was detected in 11 subjects (42.3%) and four of these patients had other co-existing resistance mechanisms; increased AXL expression was observed in 5/26 patients (19.2%), MET gene amplification was noted in 3/26 (11.5%), and one patient acquired a mutation in the phosphatidylinositol-4, 5-bisphosphate 3-kinase catalytic subunit alpha isoform (PIK3CA) gene. None of the patients exhibited EMT; however, increased CD56 expression suggesting neuroendocrine differentiation was observed in two patients. Interestingly, conversion from L858R-mutant to wild-type EGFR occurred in one patient. Seven patients (26.9%) did not exhibit any known resistance mechanisms. Patients with a T790M mutation showed a more favorable prognosis. %26lt;br%26gt;Conclusion: The mechanisms and frequency of acquired EGFR-TKI resistance in Koreans are comparable to those observed in Western populations; however, more data regarding the mechanisms that drive EGFR-TKI resistance are necessary.

• 出版日期2013-12-27