CMTM6 Overexpression is Associated with Molecular and Clinical Characteristics of Malignancy and Predicts Poor Prognosis in Gliomas

CMTM6, a previously uncharacterized protein, was identified as a critical regulator of PD-L1, which is reported as an immune checkpoint inhibitor, to modulate the T cell activities both in vitro and in vivo of other tumors. However, the role of CMTM6 has so far remained unclear in glioma. To investigate the role of CMTM6 in gliomas, we analyzed the transcriptome level, genomic profiles and its relationship with clinical practice. 1862 glioma samples with transcriptome data were enrolled in this study, including CGGA RNA-seq, TCGA RNA-seq, CGGA-microarray, GSE16011 and IVY GBM databases. Clinical information and genomic profiles containing somatic mutations and DNA copy numbers were also obtained. We found that CMTM6 expression was highly correlated with major clinical and molecular characteristics. Cases with high CMTM6 expression were more likely to be predicted as malignant entities and frequent with genomic aberrations of driver oncogenes. Moreover, gene ontology analysis based on significantly correlated genes of CMTM6 expression exhibited that CMTM6 was associated with immune responses and inflammatory activities. CMTM6 was synthetic with other immune checkpoint inhibitors. Additionally, CMTM6 was involved in immune functions via modulating T-lymphocyte-mediated anti-tumor immunity. Finally, high CMTM6 expression was associated with reduced survival time and may serve as a strong indicator of poor prognosis in gliomas. In brief, High level of CMTM6 expression is closely related to high malignant gliomas. Meanwhile, CMTM6 plays an important role in regulating T cell activation and antitumor responses. Therefore, CMTM6 is a promising target for developing immunotherapy of gliomas.