Funding for this research was provided by:
National Research Foundation of Korea (NRF-2019R1A6A1A03032888, NRF-2020R1A2C2005012, NRF-2020R1C1C1008317)
Received: 6 July 2020
Accepted: 9 November 2020
First Online: 19 November 2020
Ethics approval and consent to participate
: This study was approved by the Institution Review Board at CHA Bundang Medical Center, CHA University, before sample collection (IRB No 2011-01-001) and all women signed an informed consent form before participating in the study.
: The content of the manuscript has been approved by all the authors.
: The authors declare that they have no competing interests.