Two novel lncRNAs AF111167.2 and AL162377.1 targeting miR-21-5p mediated down expression of SYDE2 correlates with poor prognosis and tumor immune infiltration of ccRCC

Advanced clear cell Renal Cell Carcinoma (ccRCC) is notoriously known for its poor prognosis. Synapse defective protein 1 homolog 2 encoded by the SYDE2 gene is a Rho GTPase-activating protein whose functional tumorigenic significance is still unclear. Recent pan-cancer analysis using the Cancer Genome Atlas (TCGA) and the Genotype-Tissue Expression (GTEx) data showed the potential tumor-suppressing effects of SYDE2 in ccRCC. Subsequently, the TCGA, GTEx data, and human protein atlas were employed to assess the correlation between the SYDE2 expression, clinical data, and overall survival (OS) in ccRCC patients. Furthermore, microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) contributing to SYDE2 down expression were identified by expression, relationship, and survival analysis. Eventually, two novel lncRNAs, AL162377.1 and AF111167.2, targeting the miR-21-5p axis, were identified in the SYDE2 upstream non-coding RNAs (ncRNAs)-related pathway in ccRCC. The expression level of SYDE2 highly depends on the tumor immune cell infiltration and immune checkpoint expression. In summary, these data demonstrated that lncRNAs/miRNAs-mediated down-regulation of SYDE2 is related to the tumor immune infiltration. Hence, giving an insight into the prognosis of ccRCC.