Background: TREM2 was identified as a marker for tumor-associated macrophages (TAMs) and monocytes. However, there is limited information concerning the TREM2 mRNA levels correlated with the outcome and tumor-infiltrating lymphocytes in different cancers.
Methods: To explore the expression pattern and prognostic value of TREM2 in pan-cancer, We use multiple databases, including ONCOMINE, PrognoScan, Kaplan-Meier Plotter, GEPIA, and TIMER. we investigated the correlations between TREM1 expression and immune infiltration in cancers, especially kidney renal papillary cell carcinoma (KIRP), and liver hepatocellular carcinoma (LIHC)
Results: According to the results from Oncomine and TIMER datasets, in a general way, TREM2 mRNA expression is higher in the majority of the tumor and is lower in lung cancer, compared with normal adjacent tissues. A high expression level of TREM2 was beneficial to the survival of LIHC patients. Both in KIRP and LIHC, TREM2 expression levels showed significant positive correlations with infiltrating levels of macrophages and dendritic cells. It also correlated with diverse immune marker sets. We can also find that TREM2 expression was modestly associated with CD8+T cells in KIRP. However, it is related to the Treg in LIHC.
Conclusions: TREM2 may be a prognostic marker in the multitudinous tumor. Furthermore, TREM2 may interact with immune infiltration to influence patient survival in cancers like LIHC and KIRP.