Introduction: Thrombosis – the main manifestation of antiphospholipid syndrome (APS) – is at the same time observed in some patients with malignancies.

Objectives: Evaluation of prevalence of some antiphospholipid antibodies (aPL) in serum of patients with breast carcinoma and the possible correlation between aPL seropositivity and clinical symptoms.

Patients and methods: 40 patients with breast carcinoma and 38 patients with non‑malignant diseases of breast were studied. Anticardiolipin antibodies (aCL) and antibodies to β2 glycoprotein‑I (anti-β2GPI) were detected by ELISA.

Results: The aCL as well as anti-β2GPI were positive in 1 patient with breast carcinoma, who at the same time presented with symptoms of APS. In the control group 2 patients were positive for anti-β2GPI.

Conclusions: We have not observed a difference of aPL prevalence between the group of patients with breast carcinoma and controls. The association of breast cancer and aPL seropositivity deserves further investigations.