O.I. Kostyleva - Ph.D. (Med.), Senior Research Scientist, Clinical Biochemistry Laboratory, N.N. Blokhin Russian Cancer Research Center, Moscow. Е-mail: ok_olga68@mail.ru E.A. Ten - Post-graduate Student, Moscow State Medical and Dental University n.a. A.I. Evdokimov N.E. Kushlinskii - Dr.Sc. (Med.), Professor, Corresponding Member RAS, Head of the Clinical Biochemistry Laboratory, N.N. Blokhin Russian Cancer Research Center, Moscow