Received: 26 July 2018
Accepted: 3 December 2018
First Online: 6 March 2019
Ethics approval and consent to participate
: Studies involving human tissues:This study was approved by the Ethical Committee of Cangzhou Central Hospital (CZCH2015052609) and it complies with the guidelines and principles of the Declaration of Helsinki. All participants signed written informed consent.
: Not applicable.
: The authors declare that they have no competing interests.
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