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Open Access Research

Diagnostic application of PIK3CA mutation analysis in Chinese esophageal cancer patients

Zizhen Ming1, Dongxian Jiang2, Qin Hu2, Xiaojing Li2, Jie Huang2, Yifan Xu2, Yalan Liu2, Chen Xu2, Xiuguo Hua1* and Yingyong Hou2*

Author Affiliations

1 Shanghai Key Laboratory of Veterinary Biotechnology, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China

2 Department of Pathology, Zhongshan Hospital, Fudan University, Shanghai 200032, P.R. China

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Diagnostic Pathology 2014, 9:153  doi:10.1186/s13000-014-0153-4

Published: 9 August 2014

Abstract

Background

The PIK3CA gene mutation was found to associate with prognosis and might affect molecular targeted therapy in esophageal carcinoma (EC). The aim of this study is to compare different methods for analyzing the PIK3CA gene mutation in EC.

Methods

Genomic DNA was extracted from 106 surgically resected EC patient tissues. The PIK3CA mutation status (exons 9 and 20) were screened by mutant-enrich liquid chip (ME-Liquidchip), Sanger sequencing, and pyrosequencing. And all samples with mutations were independently reassessed using amplification refractory mutation system (ARMS) methods again.

Results

PIK3CA mutation rates were identified as 11.3% (12/106) by ME-Liquidchip. 10 mutations occurred in exon 9 and 2 in exon 20, including G1624A:E542K (n = 4), G1633A:E545K (n = 6) and A3140G:H1047R (n = 2). The results were further verified by ARMS methods. Among these 12 cases characterized for PIK3CA mutation, however, only 7 and 6 cases were identified by Sanger sequencing (6.6%,7/106) and pyrosequencing (5.7%,6/106), respectively.

Conclusion

Sanger sequencing and pyrosequencing are less sensitive and are not efficiently applicable to the detection of PIK3CA mutation in EC samples. Choosing between ME-Liquidchip and ARMS will depend on laboratory facilities and expertise.

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_153 webcite

Keywords:
Esophageal carcinoma; Mutation; PIK3CA gene