Are there any ethnic differences in molecular predictors of erlotinib efficacy in advanced non-small cell lung cancer?

Myung Ju Ann, Byeong Bae Park, Jin Seok Ann, Sang We Kim, Heung Tae Kim, Jong Seog Lee, Jin Hyung Kang, Jae Yong Cho, Hong Suk Song, Se Hoon Park, Chang Hak Sohn, Sang Won Shin, Jin Hyuck Choi, Chang Seok Ki, Chan Keum Park, Alison J. Holmes, Pasi A. Jänne, Keunchil Park

Research output: Contribution to journalArticle

51 Citations (Scopus)

Abstract

Purpose: This study investigated possible molecular predictors of outcome in Korean patients with advanced non-small cell lung cancer treated with erlotinib. Experimental Design: One hundred and twenty patients received erlotinib and were followed prospectively. Ninety-two tissue samples were analyzed for epidermal growth factor receptor (EGFR) gene mutations (exons 18,19, and 21), 88 for EGFR gene amplification by real-time PCR, and 75 for EGFR protein expression by immunohistochemistry. Results: The overall tumor response rate was 24.2% (complete response, 4; partial response, 25) with 56.7% of disease control rate. With a median follow-up of 23.6 months, the median time to progression (TTP) was 2.7 months and the median overall survival was 12.9 months. EGFR gene mutations were found in 26.1% (24 of 92), EGFR gene amplification in 40.9% (36 of 88), and EGFR protein expression in 72% (54 of 75). There was a strong association between EGFR gene mutations and gene amplification(γ = 0.241). Patients with EGFR gene mutations or gene amplification showed both better response rate (58.3% versus 16.2%, P < 0.001; 41.7% versus 17.3%, P = 0.012) and TTP (8.6 versus 2.5 months, P = 0.003; 5.8 versus 1.8 months, P < 0.001) and overall survival (not reached versus 10.8 months, P = 0.023; not reached versus 10.1 months, P = 0.033). By multivariate analysis, EGFR gene mutation was the only significant molecular predictor for TTP (hazard ratio, 0.47; 95% confidence interval, 0.25-0.89). Conclusions: Our findings indicate that EGFR gene mutation is a more predictive marker for improved TTP than EGFR gene amplification in erlotinib-treated Korean non-small cell lung cancer patients. Prospective studies from diverse ethnic backgrounds are required to determine the exact role of these molecular markers.

Original languageEnglish
Pages (from-to)3860-3866
Number of pages7
JournalClinical Cancer Research
Volume14
Issue number12
DOIs
Publication statusPublished - 2008 Jun 15
Externally publishedYes

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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