In the proposed project the investigators will asses whether changes in expression of selected circulating microRNAs in serum could comprise a sensitive and specific biomarker of cardiotoxicity in cancer patients treated with anthracyclines based chemotherapy.

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.

Inclusion Criteria:

• age 18-70
• stage I-III TNM (Tumor Node Metastases)

Exclusion Criteria:

• second or next cancer (except for basal cell skin cancer and CIN)
• previously treated with chemotherapy
• previously treated with radiotherapy
• acute myocardial infarction
• heart failure
• cardiomyopathy

Women with newly diagnosed breast cancer that will be treated with anthracyclines will be recruited.