SLAMF7 predicts prognosis and correlates with immune infiltration in serous ovarian carcinoma

Abstract Background: Signaling lymphocytic activation molecule family members (SLAMFs) play a critical role in immune regulation of malignancies. However, the function of SLAMFs in ovarian cancer (OV) is rarely studied. Methods: The expression analysis of SLAMFs was conducted based on the TCGA-OV and GEO databases. Immunohistochemistry (IHC) was further performed on tissue arrays (n = 98) to determine the expression of SLAMF7. Kaplan-Meier plotter and multivariate Cox regression model were used to evaluate the correlation of SLAMF7 expression with survival outcomes of patients. The molecular function of SLAMF7 in OV was further investigated using Gene Set Enrichment Analysis (GSEA). Results: SLAMF7 mRNA expression were significantly upregulated in OV tumor tissue compared to normal tissue. IHC revealed that SLAMF7 expression was located in the interstitial parts of tumor tissue, and higher SLAMF7 expression was associated with favorable survival outcomes. GSEA demonstrated that SLAMF7 is involved immune-related pathways. Further analysis showed that SLAMF7 had a strong correlation with the T cell-specific biomarker (CD3) but not with the B cell (CD19, CD22, and CD23) and NK cell-specific biomarkers (CD85C, CD336, and CD337). Furthermore, IHC analysis confirmed that SLAMF7 was expressed intumor-infiltrating T cells, and the IHC score of SLAMF7 was positively correlated with CD3 (r = 0.846, P ＜0.001). Conclusions: SLAMF7 is expressed in the interstitial components of clinical OV tissue, and higher SLAMF7 expression indicated a favorable prognosis for patients with OV. Additionally, SLAMF7 is involved in T-cell immune infiltration in OV.