Background/aim: BCL-3, upregulated in several cancers, functions as a crucial player not only in cell cycle and apoptosis, but also in metastasis. The study aimed to analyse the expression profile of BCL-3 and its interacting partners in metastatic breast cancer.

Materials and methods: mRNA expression levels were evaluated in blood samples of metastatic breast cancer patients (n=55) and in healthy control donors (n=50) by RT qPCR. SPSS 26 program was used for statistical analysis.

Results: Expression levels of BCL-3 mRNA was downregulated in metastatic breast cancers patients compared to healthy control group (p= 0.0004). Subsequently, expression levels of the NFKB1 (p= 0.0005), NFKB2 (p=0.0001), CYLD (p= 0.00042) and TP53 (p= 0.0287) were significantly lower in metastatic breast patients compared to healthy controls. CCND1 and CDH2 gene expressions were significantly upregulated in metastatic group (p=0.0009; and p= 0.0030, respectively). GSK3B, SMAD3 and TGFB1 expressions were not significantly different between groups.

Conclusion: This study indicates significant expression difference between patients and controls. The NF-κB regulators might induce the metastatic potential through interaction with the other molecules in the microenvironment, nevertheless, it is needed further research whether the importance of BCL-3 as a biomarker for metastatic breast cancer.