Subtype‐specific prognostic relevance of IL6 in basal‐like breast cancer and modulation of IL6 expression by nanobacteria‐like particles in MDA ‐ MB ‐231 cells

Abstract Breast cancer is one of the most prevalent malignancies among women worldwide. The heterogeneity of molecular subtypes of breast cancer causes differences in disease prognosis. Basal‐like is one of the most malignant breast cancer subtypes, which is usually associated with tumor aggressiveness and therapeutic limitations. Interleukin‐6 is a key inflammatory cytokine that acts in cancer progression via the IL‐6/JAK/STAT3 signaling pathway. A previous study showed that nanobacteria‐like particles (NB‐LPs) can reduce cell viability in breast cancer cells. This study aimed to evaluate the prognostic value of IL6 expression across breast cancer subtypes and to investigate the effects of NB‐LPs on MDA‐MB‐231 breast cancer cell viability and IL6 expression levels. Survival analysis was used with the KM plotter database in various subtypes of breast cancer. Cell viability and IL6 expression were measured by MTT assay and qRT‐PCR, respectively. High IL6 expression is significantly associated with a shorter Relapse‐free survival rate only in basal‐like subtypes among systemically untreated patients. Moreover, NB‐LPs significantly reduce breast cancer cell viability and IL6 expression levels in MDA‐MB‐231 cells. In conclusion, our results showed that IL6 mRNA expression level is associated with the risk of survival, which may act as a potential prognostic biomarker in basal‐like breast cancer patients. In addition, NB‐LPs can reduce cell viability and IL6 expression in vitro.