Article History
Received: 11 April 2019
Accepted: 2 July 2019
First Online: 7 August 2019
Compliance with ethical standards
: The Research Ethics Committee of this hospital gave consent to this study. Prior to diagnosis, none of patients were subjected to antitumor treatment. The written consents were eligibly gained from OS patients and in line with the Declaration of Helsinki, the study was implemented.
: The authors declare that they have no conflict of interest.