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The Clinical and Molecular Profile of ALK in NSCLC

The Clinical and Molecular Profile of ALK in NSCLC

A number of studies have examined clinical or demographic factors associated with EML4-ALK gene rearrangements. Compared with patients who have ALK-negative disease, factors associated with ALK-positive NSCLC are:

  • Younger median age (<60 years)1-5
  • Non-smoking or light smoking history1-5,7
  • Adenocarcinoma or mixed histology1,3-7
  • A solid growth pattern with signet-ring cells2,3

Data have suggested that tumours with EML4-ALK gene rearrangements generally do not have mutations in the genes for epidermal growth factor receptor (EGFR)1-4,6,7 or V-Ki-ras2 Kirsten rat sarcoma viral oncogene homologue (KRAS).3-7 However, cases of NSCLC with EGFR mutations or KRAS mutations and concomitant EML4-ALK rearrangements have also been reported.5,8,9

Despite the correlations between these clinical or histological features and ALK status, it is possible for any patient with NSCLC to have ALK-positive disease. For example, the EML4-ALK fusion gene has been found in older patients with a smoking history.2 This suggests that clinical characteristics alone cannot detect all patients and that molecular testing is essential to determine ALK status.

Currently, the exact prevalence of EML4-ALK in NSCLC is unknown (see table below), but it has been estimated that between 3% and 5% of North American patients with NSCLC have this genetic inversion.10 Data vary between studies because of differences in patient selection criteria and EML4-ALK detection methods.11

Study Nationality of patients with NSCLC No. with
Percent with 
Analytic method
Soda et al. 200712 Japanese 5/75 6.7% RT-PCR
Inamura et al. 200813 Japanese 5/221 2.2% RT-PCR
Takeuchi et al. 200814 Japanese 11/364 3.0% RT-PCR
Perner et al. 200815 Swiss and US 16/603 2.7% FISH, RT-PCR
Koivunen et al. 200816 Korean and US 8/305 2.6% RT-PCR
Korean 6/167 3.6%
US 2/138 1.4%
Shinmura et al. 200817 Japanese 2/77 2.6% RT-PCR
Rodig et al. 20092 US 20/358 5.6% FISH
Martelli et al. 20098 Italian and Spanish 9/120 7.5% RT-PCR
Wong et al. 20094 Chinese 13/266 4.9% RT-PCR
Shaw et al. 20093 US* 19/141 13.5% FISH
Boland et al. 20096 US 6/335 1.8% FISH, RT-PCR
Sakairi et al. 20101 Japanese 7/109 6.4% FISH, RT-PCR
Takahashi et al. 20107 Japanese 5/313 1.6% RT-PCR
Zhang et al. 20105 Chinese 12/103 11.6% RACE-coupled PCR sequencing
Salido et al. 201118 Spanish 2/107 1.9% FISH
Prevalence of EML4-ALK gene rearrangements in various studies

*These patients were selected for genetic screening because of their higher risk of EML4-ALK based on clinical/demographic characteristics.

FISH: fluorescence in-situ hybridisation
RACE: rapid amplification of cDNA ends
RT-PCR: reverse transcription-polymerase chain reaction



  1. Sakairi Y, Nakajima T, Yasufuku K, et al. EML4-ALK fusion gene assessment using metastatic lymph node samples obtained by endobronchial ultrasound-guided transbronchial needle aspiration. Clin Cancer Res 2010;16:4938–4945
  2. Rodig SJ, Mino-Kenudson M, Dacic S, et al. Unique clinicopathologic features characterize ALK-rearranged lung adenocarcinoma in the Western population. Clin Cancer Res 2009;15:5216–5223
  3. Shaw AT, Yeap BY, Mino-Kenudson M, et al. Clinical features and outcome of patients with non-small-cell lung cancer who harbour EML4-ALK. J Clin Oncol 2009;27:4247–4253
  4. Wong DW-S, Leung EL-H, So KK-T, et al. The EML4-ALK fusion gene is involved in various histologic types of lung cancers from non-smokers with wild-type EGFR and KRAS. Cancer 2009;115:1723–1733
  5. Zhang X, Zhang S, Yang X, et al. Fusion of EML4 and ALK is associated with development of lung adenocarcinomas lacking EGFR and KRAS mutations and is correlated with ALK expression. Mol Cancer 2010;9:188
  6. Boland JM, Erdogan S, Vasmatzis G, et al. Anaplastic lymphoma kinase immunoreactivity correlates with ALK gene rearrangement and transcriptional up-regulation in non-small cell lung carcinomas. Hum Pathol 2009;40:1152–1158
  7. Takahashi T, Sonobe M, Kobayashi M, et al. Clinicopathologic features of non-small-cell lung cancer with EML4-ALK fusion gene. Ann Surg Oncol 2010;17:889–897
  8. Martelli MP, Sozzi G, Hernandez L, et al. EML4-ALK rearrangement in non-small cell lung cancer and non-tumor lung tissues. Am J Pathol 2009;174:661–670
  9. Yang J, Zhang X, Su J, et al. Concomitant EGFR mutation and EML4-ALK gene fusion in non-small cell lung cancer. Poster presented at the American Society of Clinical Oncology conference, June 3-7 2011, Chicago, IL [Abstract 10517]
  10. Garber K. ALK, lung cancer, and personalized therapy: portent of the future? J Natl Cancer Inst 2010;102:672–675
  11. Horn L, Pao W. EML4-ALK: Honing in on a new target in non-small-cell lung cancer. J Clin Oncol 2009;27:4232–4235
  12. Soda M, Choi YL, Enomoto M, et al. Identification of the transforming EML4-ALK fusion gene in non-small-cell lung cancer. Nature 2007;448:561–567
  13. Inamura K, Takeuchi K, Togashi Y, et al. EML4-ALK fusion is linked to histological characteristics in a subset of lung cancers. J Thorac Oncol 2008;3:13–17
  14. Takeuchi K, Choi YL, Soda M, et al. Multiplex reverse transcription-PCR screening for EML4-ALK fusion transcripts. Clin Cancer Res 2008;14:6618–6624
  15. Perner S, Wagner PL, Demichelis F, et al. EML4-ALK fusion lung cancer: a rare acquired event. Neoplasia 2008;10:298–302
  16. Koivunen JP, Mermel C, Zejnullahu K, et al. EML4-ALK fusion gene and efficacy of an ALK kinase inhibitor in lung cancer. Clin Cancer Res 2008;14:4275–4283
  17. Shinmura K, Kageyama S, Tao H, et al. EML4-ALK fusion transcripts, but no NPM-, TPM3-, CTCL-, ATIC-, or TGF-ALK fusion transcripts, in non-small cell lung cancer. Lung Cancer 2008;61:163–169
  18. Salido M, Pijuan L, Martínez-Avilés L, et al. Increased ALK gene copy number and amplification are frequent in non-small cell lung cancer. J Thorac Oncol 2011;6:21–27