Tehran University of Medical Sciences Basic & Clinical Cancer Research 2228-6527 13 1 2022 01 04 55 62 Ali Aycicek Pediatric Hematology Oncology Tuba Nur Tahtakesen Basaksehir Cam and Sakura City Hospital Pediadric Hematology/Oncolog Clinic 34480, Istanbul, TURKEY. Cengiz Bayram Basaksehir Cam and Sakura City Hospital Pediadric Hematology/Oncolog Clinic 34480, Istanbul, TURKEY. 2021 03 07 2021 09 20 Aim: To investigate invitro ursodeoxy cholic acid (UDCA) and N-acetyl cystein (NAC) effect on blast cell viability in children newly diagnosed with acute lymphoblastic leukemia (ALL). Patients and Methods: Samples were obtained from a total of 52 newly diagnosed ALL patients aged 1 to 17 years. UDCA and NAC were added at clinical relevant concentrations (0-300 micrograms) onto 5x10^5 cells were treated at room temperature in dark place. Untreated and treated cells were stained with 7AAD PE and analyzed by flow cytometry. Results: Median (IQR) blast percentage and incubation time were 90% (11) and 18 (1.5) hours, respectively.  Dead/live blast cells ratio (7AAD+) was lower in lymphoblasts treated with all NAC concentration than untreated controls (p < 0.001). The use of NAC was noted to,  regardless of concentration, contributed to lymphoblasts viability. On the contrary, dead/live blast cells ratio in samples treated with UDCA at the above-mentioned concentrations was relatively high, suggesting the protection role for both hepatotoxicty and against leukemia. However, the difference was not statistically significant (P >0.05). There was also no correlation between different doses of  UCDA and NAC  regarding blast cell viability (P > 0.232). Conclusion: The present study showed that in vitro  NAC use had a protective effect on lymphoblast viability in newly diagnosed ALL patients before start of chemotherapy, and also patient-derived ALL cells can be successfully analyzed ex vivo in a short  and different period of time without loss of blasts. https://bccr.tums.ac.ir/index.php/bccrj/article/view/379 https://bccr.tums.ac.ir/index.php/bccrj/article/download/379/476