Resumen de Impact of anthracycline‑based chemotherapy on RB1 gene methylation in peripheral blood leukocytes and biomarkers of oxidative stress and infammation in sarcoma patients

Anita Pokupec Bilić, Morana Mikloš, Ivana Tonković Đurišević, Ivan Bilić, Luka Simetić, Krešimir Blažičević, Davorin Herceg, Sandra Radić Brkanac, Ana Marija Domijan

• Purpose We investigated the impact of anthracycline-based chemotherapy on methylation status of RB1 gene in peripheral blood leukocytes together with parameters of oxidative stress and infammation in sarcoma patients.

  Patients/methods Blood samples were collected from 51 consecutive newly diagnosed sarcoma patients admitted to University Hospital Center Zagreb (Zagreb, Croatia) for frst-line chemotherapy before the frst cycle and post-chemotherapy. Methylation and copy number variation (CNV) of leukocyte RB1 gene were assessed using MS-MLPA probes. In addition, in blood samples, parameters of oxidative stress (ROS, MDA, SOD, and GSH) and infammation (CRP, WBC, and NBC) were followed.

  Results In pre-chemotherapy samples, no CNVs and aberrant methylation of CpG106 promoter region of RB1 gene were detected; however, one patient had hypermethylation (by approximately 10%) of imprinted locus CpG85 in intron 2 of RB1 gene. In addition, a very good correlation of the tumor burden and CRP and tumor burden and GSH was found. The anthracyclinebased chemotherapy reverts methylation of RB1 gene-imprinted locus CpG85 to normal level. Moreover, infammation and oxidative stress parameters such as CRP, WBC, ROS, and MDA were signifcantly decreased in post-chemotherapy samples.

  Conclusion This single-centered study on a cohort of consecutive sarcoma patients indicates that sarcoma patients can have aberrant germline DNA methylation and confrms the relationship of tumor burden with infammation and oxidative stress. The applied chemotherapy protocols reverted RB1 gene methylation to normal level and decreased the level of infammation and oxidative damage, thus indicating chemotherapy beneft to the patient’s health status.