Аннотация:Background: We monitored some biochemical parameters to assess hepatotoxicity of anthracycline chemotherapy in patients with breast cancer. Methods: The study included 30 patients (32-72 years, median age 52.0±12.8 years) with st. II-III breast cancer receiving 4 cycles of anthracycline (AC) chemotherapy (CT). Serum levels of total protein, albumin, bilirubin and its fractions, alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase, C-reactive protein (CRP), alpha-1 antitrypsin (A1AT) (Vitros 5600, USA) and lactate dehydrogenase (LDH) (Cobas Integra 400 plus, Switzerland) were determined before and after anthracycline injections (days 2 and 5) and after 4 CT cycles. Statistical processing of results was performed using the Statistica 6.0 program. Results: The levels of all parameters were within the reference range before treatment, except for 3 pts with moderately increased LDH activity and normal ALT and AST. No changes were observed in 29 (96.7%) pts after cycle 1 CT. 1 (2.6%) patient showed an increase in AST by 2.54 times, in ALT – by 2.88 times on day 2 after AC injection, with restoration to initial values on day 5. Day 2 of the 4th CT cycle: total protein and albumin decreased in 7 (23.3%) pts by 15.8% and 24.3%, respectively; in 30% (9) AST increased by 3 times (p < 0.01) and ALT by 3.2 times (p < 0.01), in 60% (18) LDH increased by 1.4 times (p < 0.01), including pts with initially high LDH. Levels of bilirubin and its fractions did not change significantly. Further increase of AST by 3.6 times (p < 0.001), ALT by 3.8 times (p < 0.05), LDH by 2.2 times (p < 0.05), as well as dysproteinemia, were registered by the end of cycle 4. Levels of CRP and A1AT increased by 2.7 and 2 times (p < 0.05), respectively, in 26.6% (8) pts, including cases with normal enzyme activity, already after the first AC injection. The highest levels were observed by the end of cycle 4: CRP increased by 4 times (p < 0.001), and А1АТ – by 3.4 times (p < 0.05). Conclusions: An increase in levels of CRP and A1AT at the initial stage of anthracycline CT in patients with breast cancer, accompanied by further hyperfermentemia, allows considering these indicators as early predictors of the hepatotoxicity risk.