Abstract Background The centromere protein O (CENPO) is an important member of the centromere protein family. However, the role of CENPO in pan–cancer and immune infiltration has not been reported. Here, we investigated the role of CENPO in pan–cancer and further validated its role in lung adenocarcinoma (LUAD) by in vitro experiments. Method The UCSC Xena database and The Cancer Genome Atlas (TCGA)–LUAD data were used to assess the expression levels of CENPO. The potential value of CENPO as a diagnostic and prognostic biomarker for pan–cancer was evaluated using TCGA data and the GEPIA database. The -expression profiles of LUAD patients and the corresponding clinical data were downloaded for correlation analysis. The role of CENPO in immune infiltration was investigated using the UCSC Xena database. Subsequently, qRT–PCR was performed to detect the expression of CENPO. Cell proliferation, migration, and invasion were determined using CCK–8, wound–healing assay, and transwell assay, respectively. Results CENPO is highly expressed in most cancers, and the upregulation of CENPO is associated with poor prognosis in many cancers. CENPO expression correlates with age, TNM stage, N stage, T stage, and receipt of radiotherapy in LUAD patients, and LUAD patients with high CENPO expression have poorer overall survival (OS) and disease–free survival (DFS). In addition, CENPO expression is associated with immune cell infiltration and immune checkpoint inhibitors. Moreover, the expression of CENPO was closely related to the expression of tumor mutational load and microsatellite instability. In vitro experiments showed that CENPO expression was increased in LUAD cell lines and that knockdown of CENPO significantly inhibited the proliferation, cell invasion, and migration ability of LUAD cells. Conclusion CENPO may be a potential pan–cancer biomarker and oncogene, especially in LUAD. In addition, CENPO is associated with immune cell infiltration and may serve as a new molecular therapeutic target and effective prognostic marker for LUAD.
