Funding for this research was provided by:
Korea Health Industry Development Institute (HI16C0443)
Received: 1 May 2018
Accepted: 29 May 2019
First Online: 17 June 2019
Ethics approval and consent to participate
: This study was approved by the institutional review board (IRB) of Seoul St. Mary’s Hospital. The IRB waived the requirement to obtain informed consent from participants, because we used de-identified left over samples obtained from routine examination.
: Not applicable.
: The authors declare that they have no competing interests.