Angiopoietin-Like Protein 2 Serves as an Independent Prognostic Biomarker and Correlates with Immune Infiltration in Osteosarcoma

Osteosarcoma mostly occurs in adolescents, with high disability and mortality rates and poor prognosis. Angiopoietin-like protein 2 (ANGPTL2) is a secreted glycoprotein protein, which plays important roles in cellular processes and various diseases. Microarray gene expression data GSE16088 and GSE36001 were downloaded from Gene Expression Omnibus (GEO, http://www.ncbi.nlm.nih.gov/geo). The Complex Heatmap package was used to construct heatmaps, the gglot2 R language package to plot volcanoes and differential expression data, and the “VennDiagram” R language package to plot Wayne plots. Western booting and qRT-PCR was used to detect ANGPTL2 expression in osteosarcoma tissues. proteins. In addition, the GeneMANIA database (http://www.genemania.org) was cited to predict the ANGPTL2 interaction network. We used the single-sample gene-set enrichment analysis (ss GSEA) algorithm to quantify the immune infiltration of osteosarcoma. In the GSE16088 database there were 5005 that met the selected threshold of |log2(FC)| > 1 and P <0.05, of which 2719 were highly expressed and 2286 were lowly expressed. WB and qRT-PCR results showed that ANGPTL2 was significantly up-regulated in osteosarcoma tissues. ssGSEA showed that high ANGPTL2 expression in osteosarcoma patients had a worse prognosis. ssGSEA showed that high ANGPTL2 expression was correlated with Mast cells and Th1 cells. Collectively, ANGPTL2 can be an independent prognostic biomarker and correlated with immune infiltration in osteosarcoma.