TNFSF12 is associated with breast cancer prognosis and immune cell infiltration.

Background: Breast cancer (BRCA) is one of the most common cancers in women and is the leading cause of cancer-related deaths in women. TNFSF12, originally a member of the TNF superfamily, is considered a key molecule that is associated with poor prognosis of many cancers. However, its role in progression of BRCA remains unclear.

Methods: In this study, the expression profile and clinical information of TNFSF12 across various cancers were obtained from The Cancer Genome Atlas (TCGA) database. Differences in TNFSF12 expression levels between carcinoma and paraneoplastic cancers were compared, and its association with prognosis was examined. Functional enrichment analysis was conducted to explore the potential signaling pathways and biological functions linked with TNFSF12. Moreover, the correlation between TNFSF12 and immune cell infiltration, response to immune checkpoint inhibitors (ICIs), and response to chemotherapy were evaluated. TNFSF12 level in BRCA and normal serum was detected by ELISA.

Results: TNFSF12 was lowly expressed in BRCA and is significantly associated with PAM50. TNFSF12 low expression correlates with poor overall survival, particularly among HER2-positive patients. Patients with high level of TNFSF12 expression are usually accompanied with elevated levels of various immune cells, including CD8 T cells, cytotoxic cells, DCs, eosinophils, iDCs, mast cells, neutrophils, NK CD56bright cells, NK cells, pDC, T cells, Tem, and TFH Th17 cells, and exhibit sensitivity to immune checkpoint inhibitors. Functional enrichment analysis indicates significant activation of KRAS signaling, TNFA signaling via NFKB, and epithelial-mesenchymal transition (EMT) in the high TNFSF12 expression group, while MTORC1 signaling, MYC, G2M checkpoint, and E2F targets are inhibited. Furthermore, patients in the low expression group demonstrate higher sensitivity to paclitaxel and rapamycin, whereas those in the high expression group show increased sensitivity to erlotinib and foretinib. ELISA analysis also confirmed a significant decrease of TNFSF12 protein levels in BRCA patients.

Conclusion: This study presents a comprehensive analysis of the close correlation between TNFSF12 and prognosis, immune response, as well as the effectiveness of chemotherapeutic agents in BRCA patients.