CK2 expression in cancer and associated clinical characteristics.

e15156 Background: The protein casein kinase 2 (CK2) is a ubiquitously expressed, highly pleiotropic kinase. CK2 may have incredibly varied substrate specificity and catalytic activity, as it functions as both a tetrameric and monomeric enzyme. CK2 participates in many cellular processes such as cellular proliferation, growth, and survival, and has significant potential to assist in oncogenic signaling. We and others have demonstrated CK2 gene and protein overexpression, and sometimes underexpression, in a variety of cancers. Here we investigate how the expression of CK2 subunits in cancer is associated with clinical characteristics in several distinct cancer types. Methods: Data analysis was performed on 32 non-overlapping cancer datasets obtained from The Cancer Genome Atlas (TCGA) and Broad GDAC Firehose Legacy projects, one dataset from Cancer Cell Line Encyclopedia (CCLE), and normal tissue datasets from Gene Expression Omnibus. Statistical analysis was performed using RStudio to explore the relationship between the expression levels of the three CK2 alpha transcripts (CSNK2A1, CSNK2A2, and CSNK2A3) and beta transcripts (CSNK2B) with sample clinical characteristics provided by TCGA/Broad. Relationships between CK2 expression and cancer-type specific characteristics were also explored, such as KRAS mutations in colorectal adenocarcinoma and serum AFP at sample procurement in hepatocellular carcinoma. CCLE data was used to explore correlations between cancer-type dependent CK2 gene expression and half maximal inhibitory concentration (IC50) of over 250 anticancer drugs. Tumor Immune Estimation Resource (TIMER) 2.0 was used to assess the relationship between CK2 subunit expression and tumor immune infiltration. Results: As seen in our previous analysis, CK2 transcripts were upregulated in the majority of cancer types analyzed. We also found that CK2 transcript upregulation correlated with worse survival outcomes in several previously unstudied cancers. CK2 expression differed significantly between cancer subtypes such as in ductal carcinoma and lobular carcinoma in breast cancer. CK2 expression significantly correlated with tumor grade, TNM staging, clinical staging in certain cancer types. CK2 expression significantly correlated with altered response to various anticancer drugs in certain cancers. CK2 expression was associated with both increased and decreased immune infiltration in a variety of cancers. Conclusions: Overall, this study demonstrates that CK2 transcript expression correlates with a variety of cancer-type dependent characteristics and clinical outcomes. As a result, CK2 may be useful as a prognostic biomarker and therapeutic target.