Circulating MicroRNA as Biomarker of Cardiotoxicity in Breast Cancer

Blood will be taken 1. before anthracycline based chemotherapy administration 2. at the middle of anthracycline treatment (before 3rd and/or 5th cycle of drugs infusion) 3. after anthracycline chemotherapy cessation 4. 6 months after chemotherapy cessation if an end point occurs 5. 12 months after chemotherapy cessation if an end point occurs Echocardiography will be performed 1. before anthracycline based chemotherapy administration 2. after anthracycline based chemotherapy cessation 3. 6 months after anthracycline based chemotherapy cessation 4. 12 months after anthracycline based chemotherapy cessation if no end point was observed earlier The investigators will perform high-throughput miRNA(microRNA) expression profiling of serum samples - called training set. Training set will consist of sera of 30 patients who has reached an end point. Training set will be sequenced using next generation sequencing. Training set will be used to derive a miRNA signature capable of separating early cardiotoxicity patients from healthy ones. MiRNA signature will be validated using validation set.