Received: 13 January 2019
Accepted: 3 September 2019
First Online: 12 September 2019
Ethics approval and consent to participate
: Anonymous use of redundant tissues is part of the standard treatment agreement with patients at the study hospital when no objection is expressed. The Fukuoka University Hospital Institutional Ethics Committee approved the study protocol (approval number 12–7-13), which allowed a waiver of informed consent for the study.
: Not applicable.
: The authors declare that they have no competing interest related to this work.