Background: Breast cancer remains a leading malignancy worldwide, and inflammation-related pathways are increasingly recognized as contributors to tumor progression and immune modulation The NLRP3 inflammasome and the IL-33/ST2 axis have been implicated in breast cancer biology.

Objective: To assess serum NLRP3 and ST2 levels in breast cancer patients and their association with clinicopathological features.

Methods: A cross-sectional study was performed including 90 women with newly diagnosed breast cancer and 60 healthy controls. Serum NLRP3 and ST2 were measured using ELISA, and levels were compared between groups and across grade, stage, and hormonal receptor status.

Results: Serum NLRP3 was significantly higher in patients than controls (120.68±1.23 vs 80.13±2.79 pg/mL; p<0.001). Serum ST2 was also higher in patients (0.447±0.111 vs 0.143±0.013 ng/mL; p=0.01). NLRP3 differed across grades with significant differences between Grade I vs III (p=0.03) and Grade II vs III (p=0.045), while stage-wise differences were not significant (p=0.75). ST2 differed across grades (Grade I vs II p=0.05; Grade I vs III p=0.05) but not across stages (p=0.9). No significant differences were observed for NLRP3 or ST2 by L.M.N., ER, PR, or HER2 status, and there was no correlation between ST2 and NLRP3 (r=0.046; p=0.68).

Conclusion: Serum NLRP3 and ST2 were significantly higher in breast cancer patients than controls, supporting an association with systemic inflammation. NLRP3 varied significantly by tumor grade (lower in Grade III), while both biomarkers showed no significant differences by stage, lymph node status, or ER/PR/HER2 profile and were not correlated, suggesting they reflect broader inflammatory responses rather than tumor burden alone.