Cyclooxygenase-2 and Bcl-2 expression in patients with triple-negative breast cancer

Introduction. Triple-negative breast cancer (TNBC) is a rare type of breast cancer associated with lack of expression of estrogen and progesterone receptors and the HER2 protein. It is characterized by a poor outcome and chemotherapy resistance. Cyclooxygenase-2 (COX-2) is a constitutional enzyme responsible for prostaglandin synthesis, present in neoplastic cells and premalignant lesions. The B-cell lymphoma 2 (Bcl-2) protein is considered one of the most potent apoptosis-regulating agents, assuring body homeostasis. Material and methods. The aim of the present study was to evaluate the immunohistochemical (IHC) profile of COX-2 and Bcl-2 expression in patients suffering from TNBC in order to obtain more detailed data on additional factors negatively influencing TNBC outcome. The IHC evaluation of COX-2 and Bcl-2 expression among 21 women with diagnosis of TNBC was performed. Results. The most common histological subtype was invasive ductal cancer of no special type. COX-2 was present in all examined samples with moderate to strong expression detected in 20 of 21 cases. There was a positive correlation between histological grade (G) and COX-2 expression (p = 0.002). Bcl-2 was present in all examined samples. The analysis showed that tumours presenting highly positive expression of Bcl-2 accounted for the majority of examined cases (57.2%). Conclusions. The achieved results might lead to a conclusion that COX-2 and Bcl-2 high expression in TNBC may be linked to tumour aggressiveness and poor overall survival. However, before their consideration as additional markers to be used in routine histological examinations and breast cancer grading, it will be necessary to undertake further studies.