R.M.Gorbacheva Memorial Research Institute of Pediatric Oncology, Hematology and Transplantation, St. Petersburg State I. Pavlov Medical University, St. Petersburg, Russia
Sponsorships or competing interests that may be relevant to content are disclosed at the end of this article.
Received June 30, 2015
Received in revised form July 16, 2015
Accepted July 20, 2015