Text and Data Mining valid from 2018-05-09
Received: 21 January 2018
Accepted: 3 May 2018
First Online: 9 May 2018
Ethics approval and consent to participate
: The Ethics Committee at Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College approved the study in accordance with the Declaration of Helsinki. All individuals gave written informed consent for participation in the study.
: The authors declare that they have no competing interests.
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