RESUMO
BACKGROUND: Breast cancer is one of the most common cancers. Leukemia inhibitory factor (LIF) is considered as one of the effective factors in the growth of breast cancer, and anti-leukemia inhibitory factor antibody is considered as one of the treatment options for this type of cancer. METHODS: Mice models of breast cancer were made with 4T1 cell line and were randomly divided into four groups. The first group included the mice that received anti-LIF (Anti LIF group). The mice in the second group received anti-LIF and doxorubicin (Anti LIF & DOX). The mice in the third group received only doxorubicin (DOX). Finally, the mice in the fourth group did not receive any intervention. 22 days after tumor induction, some of the mice were killed, and their tumor tissues, lymph nodes, and spleens were separated for evaluating P53, Caspase-3, TIM-3, LAG-3, CTLA-4, and PD-1 genes expression. The percentage of regulatory T cells and level of interferon gamma (IFN-γ) and transforming growth factor-beta (TGF-ß) were evaluated. The rest of the mice were kept to check the tumor size and their survival rate. RESULTS: The proposed intervention did not have any significant effect on the tumor growth and the survival rate. However, the expression of P53 gene and Caspase-3 in the tumor tissue of the Anti LIF group had a significant enhancement. In tumor tissues and lymph nodes, the expression of T-bet, PD-1, TIM-3, and LAG-3 genes in the Anti LIF group showed a significant increase. There was no significant difference between groups in the percentage of regulatory T cells and level of IFN-γ and TGF-ß. CONCLUSIONS: The proposed interventions were able to have a direct effect on tumors, but no significant effect was observed on the immune system.