J Cancer 2020; 11(6):1525-1531. doi:10.7150/jca.36580

Research Paper

Comparison of EML4-ALK fusion gene positive rate in different detection methods and samples of non-small cell lung cancer

Shan Lu1,2, Can Lu1,2, YuXuan Xiao3, Wei Zhu1,2, QiuYan He1,2, Bin Xie1,2, JianHua Zhou1,2, YongGuang Tao4,5,6, Shuang Liu7, DeSheng Xiao1,2✉

1. Department of Pathology, Xiangya Hospital, Central South University, Changsha, Hunan 410078 China
2. Department of Pathology, School of Basic Medicine, Central South University, Changsha, Hunan 410078 China
3. Hengyang medical college, university of south China, Hengyang, Hunan 421001 China
4. Cancer Research Institute, School of Basic Medicine, Central South University, Changsha, Hunan, 410078 China
5. Key Laboratory of Carcinogenesis and Cancer Invasion (Central South University), Ministry of Education, Hunan, 410078 China
6. Key Laboratory of Carcinogenesis (Central South University), Ministry of Health, Hunan, 410078 China
7. Department of Oncology, Institute of Medical Sciences, Xiangya Hospital, Central South University, Changsha, Hunan, 410008 China

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Citation:
Lu S, Lu C, Xiao Y, Zhu W, He Q, Xie B, Zhou J, Tao Y, Liu S, Xiao D. Comparison of EML4-ALK fusion gene positive rate in different detection methods and samples of non-small cell lung cancer. J Cancer 2020; 11(6):1525-1531. doi:10.7150/jca.36580. Available from https://www.jcancer.org/v11p1525.htm

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Abstract

Objective: To evaluate differences of EML4-ALK positive rates in tissues samples between immunohistochemistry, reverse transcriptase polymerase chain reaction and the next-generation sequencing method. Besides, to compare the differences of EML4-ALK positive rates in blood samples and tissue samples by next-generation sequencing. The results provide a basis for the selection of a suitable EML4-ALK fusion gene detection method.

Methods: Immunohistochemistry analysis of EML4-ALK in tumors was performed on samples from 2631 patients with non-small cell lung cancer. The mutation of EML4-ALK in the tissue samples of 399 patients with non-small cell lung cancer was detected by reverse transcription polymerase chain reaction. Next-generation sequencing was used to detect the mutation of EML4-ALK in 1505 non-small cell lung cancer patients, including 1208 tissue samples and 297 blood samples.

Results: The positive incidence of EML4-ALK by immunohistochemistry was 7.11% (187/2631). Histologically, 9.51% (170/1787) of the samples were lung adenocarcinomas, and 2.01% (17/844) were squamous cell carcinomas. The positive rate of EML4-ALK was 8.52% (34/399) in 399 patients with non-small cell lung cancer, as detected by reverse transcription polymerase chain reaction; the mutation rate of adenocarcinoma was 11.62% (33/284), and the mutation rate of squamous cell carcinoma was 0.86% (1/115). In 1208 patients with non-small cell lung cancer with tissue samples, the positive rate of EML4-ALK was 4.88% (59/1208), as determined by next-generation sequencing, the mutation rate of adenocarcinoma was 5.84% (58/994), and the mutation rate of squamous cell carcinoma was 0.47% (1/214). The positive rate of EML4-ALK detected by reverse transcription polymerase chain reaction was higher than that detected by immunohistochemistry. Compared with the next-generation sequencing results, the positive rates of EML4-ALK detected by immunohistochemistry and reverse transcription polymerase chain reaction were higher, and the differences were significant (p<0.05). In blood samples from 297 patients with non-small cell lung cancer, the positive rate of EML4-ALK detected by next-generation sequencing was 3.70% (11/297), the mutation rate of adenocarcinoma was 3.82% (10/262), and the mutation rate of squamous cell carcinoma was 2.86% (1/35). The EML4-ALK positive rate of the tissue samples was thus higher than that of the blood biopsy samples.

Conclusion: Among the three methods for detecting EML4-ALK, reverse transcription polymerase chain reaction has the highest positive rate, followed by immunohistochemistry, and next-generation sequencing has the lowest positive rate. The positive detection rate of EML4-ALK in tissue samples by next-generation sequencing was higher than that in blood samples.

Keywords: EML4-ALK fusion gene, immunohistochemistry, reverse transcription-polymerase chain reaction, next-generation sequencing, non-small cell lung cancer