Aim: The aim of the study is to classify tumors into four main molecular subtypes using immunohistochemistry and in situ hybridisation methods, as well as to determine frequency of different carcinoma subtypes. Introduction: Four molecular subtypes of breast carcinoma can be identified: Luminal A and Luminal B (hormone receptors positive), HER2 enriched (HER2 overexpression) and Triple Negative / Basal-like (absence of HER2 amplification and steroid receptors expression). Materials and Methods: Cross-sectional study, conducted in Institute of pathology, Medical Faculty, University in Belgrade, during the ten months period in 2017, included 337 patients with diagnosed breast carcinoma. Using the methods of immunohistochemistry, all four markers (estrogen, progesteron, HER2, and Ki67) were evaluated on breast carcinoma tissues. As additional methods, “in situ” hybridisation (FISH, SISH) was used in cases if HER2 oncoprotein results on immunohistochemistry were equivocal. Results: Luminal A, Luminal B, HER2 enriched, and Triple Negative carcinomas were present in 133 (39,45%), 147 (43,62%), 22 (6,5%), 34 (10,08%) cases, respectively. For 55 (16,35%) cases, in situ hybridisation had been done in order to classify carcinomas in proper molecular subtype. Conclusion: Frequency of molecular subtypes of breast carcinomas in our study are similar to literature data for European countries. Breast carcinoma subtyping has prognostic and predictive values for further patient treatment, and should be done in institutions with adequately trained personnel and equipment, in order to achive best results in the shortest time.

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.