Oncogenic and Immunological Roles of FRS2 and its Potential Value in Retroperitoneal Liposarcoma: from Bioinformatics Analysis to Clinicopathological Evidence.

Background: Retroperitoneal liposarcoma (RLPS) is a rare malignancy with no effective treatment beyond surgical intervention. Identifying novel therapeutic targets and prognostic markers is critical to improving outcomes. Fibroblast growth factor receptor substrate 2 (FRS2), located near MDM2 on chromosome 12q13-15, has a biological role and prognostic value in liposarcoma, which remain to be fully explored. Methods: Bioinformatics tools were used to analyze the differential expression of FRS2 across various malignancies using public databases, such as GTEx, TCGA, and cBioPortal. In sarcomas (SARC), clinicopathological features, prognostic outcomes, co-expressed genes, levels of tumor-infiltrating immune cells, immunostimulators, major histocompatibility complex (MHC) molecules, and immunochemokines were extracted from multiple public databases. Tumor specimens from 82 RLPS patients at our sarcoma center were collected, and FRS2 expression was assessed through immunohistochemistry. Results: FRS2 was found to be upregulated and amplified in most cancers. GEPIA 2 analysis showed significant variation in FRS2 mRNA expression across cancer types, especially in sarcomas (SARC). Lower FRS2 expression in SARC was correlated with improved overall survival (OS) and disease-free survival (DFS). FRS2 may affect the tumor immune microenvironment, inhibiting immune cell infiltration and promoting immune evasion. In our RLPS cohort, FRS2 overexpression was observed in 58.53% (48/82) of cases and was correlated with age (P = 0.009). High FRS2 expression was associated with poorer OS and DFS (P = 0.049 and P < 0.001, respectively), and multivariate analysis confirmed FRS2 as an independent prognostic factor. Conclusion: FRS2 may serve as a potential prognostic biomarker and therapeutic oncogene target. Additionally, FRS2 could play a role in immune cell infiltration in SARC and represents a promising immunotherapeutic target for cancer treatment.