Investigation of DNA methylation profiles of pediatric acute lymphoblastic leukemia patients

Malignancies are neoplastic masses that occur due to the uncontrolled and unlimited proliferation of cells, that can invade surrounding tissues and metastasize. Leukemia, on the other hand, is a malignant disease that originates from the hematopoietic stem cells in the bone marrow characterized by the excessive production and circulation of immature and abnormal blood cells (blasts). Acute lymphoblastic leukemia (ALL) is the most common type of leukemia in childhood. Numerous academic studies have been conducted on leukemias. Advances in diagnosis and treatment have been achieved through the development of new technologies that have a significant impact on the morbidity and mortality rates, greatly affecting the lives of patients with this disease. In our study, global DNA methylation levels of ALL patients in the pediatric age group were examined. The change in methylation with the effect of chemotherapeutics used in the treatment and follow-up process was investigated and its importance in diagnosis and treatment was discussed in the light of the literature. Our study was designed as a prospective study. A total of 121 cases were included in the study, comprising 23 patients in the maintenance phase of ALL treatment (gruop 1), 49 patients who had completed ALL treatment (gruop 2), and the control gruop consisting of 49 healthy volunteers without any chronic diseases (gruop 3). DNA methylation was studied with the remaining material from the 2 mL EDTA tube taken for the hemogram when the patients came for their routine control. Demographic characteristics, anthropometric measurements and hemogram parameters of the cases were recorded. DNA methylation values in the groups included in the study were compared, and the methylation values of ALL patients who received maintenance treatment and whose treatment was terminated were found to be significantly higher than the healthy control group. Methylation mean and standard deviation values were 39.61 ± 11.39% in patients receiving maintenance therapy; It was found to be 36.30 ± 3.71% in patients whose treatment was completed and 17.07% ± 0.86% in the control group. It was observed that the DNA methylation of the patients whose maintenance treatment was completed continued. Although time has passed since chemotherapy, it has been predicted that the effects of chemotherapy drugs on DNA continue. In conclusion, it is seen that methylation states in DNA may be affected by chemotherapeutics in acute lymphoblastic leukemias, and this effect persists even though it decreases over time after the treatment is stopped.