Pan-Cancer Analysis and Functional Characterization Identify SLC15A4 as a Novel Prognostic Biomarker and Therapeutic Target.

SLC15A4 is a transporter protein known to be involved in immune regulation, but its role in cancer is not well understood. This study aimed to thoroughly investigate SLC15A4 across different cancers, focusing on its expression levels, link to patient survival, genetic changes, biological functions, and connection to the immune environment and treatment response. We combined large-scale data analysis from public databases with lab experiments in breast cancer (BRCA) cells. Our results showed that SLC15A4 is often present at high levels in tumors, and this high level was strongly linked to poorer patient survival. It was also connected to the presence of immune cells and how sensitive tumors were to certain drugs, suggesting it could serve both as a survival predictor and a player in the immune environment. Our in vitro experiments demonstrate distinct SLC15A4 expression levels in different BRCA cell lines, and computer-based screening pinpointed potential drugs that could block it. In conclusion, SLC15A4 is an important indicator of patient outcomes and a promising target for new treatments, especially in BRCA and lower-grade glioma (LGG).