CK2 expression gastrointestinal cancer: Exploring clinical characteristics and cancer genetics.

834 Background: The expression of protein kinase CK2 subunits (CSNK2A1, CSNK2A2, CSNK2A3, and CSNK2B) in gastrointestinal cancers has not been fully characterized. In this study, we seek to evaluate how changes in CK2 subunit expression are associated with GI cancer clinical characteristics and genetics. Methods: Data analysis was performed with data from The Cancer Genome Atlas (TCGA). R version 4.2.2 was used for analysis. We provide an analysis of several cancer cohorts looking at CK2 subunit expression, as well as cancer mutations, copy number alterations, and clinical characteristics. Results: From the TCGA datasets containing mRNA expression data, we assessed hepatocellular carcinoma (n=361), colorectal adenocarcinoma (n=339), gastric adenocarcinoma (n=306) and diffuse type gastric adenocarcinoma (n=69), pancreatic adenocarcinoma (n=169), esophageal adenocarcinoma (n=89) and squamous cell carcinoma (n=95), and cholangiocarcinoma (n=36). We explored associations between CK2 subunit expression and GI cancer-specific known driver mutations, of which we report the following significant findings (p < 0.05 for all). Mutations in TP53 were associated with increased expression of CSNK2A1 in hepatocellular carcinoma and stomach adenocarcinoma, increased CSNK2A2 in colorectal adenocarcinoma, and CSNK2B in colorectal adenocarcinoma, pancreatic adenocarcinoma, and stomach adenocarcinoma. Mutations in KRAS were associated with increased expression of CSNK2A1 and CSNK2B in pancreatic adenocarcinoma. Mutations in BRAF were associated with decreased expression of CSNK2A2 and CSNK2B in colorectal adenocarcinoma. We also noted significant changes in CSNK2 subunit expression when looking at mutations and copy number alterations in signaling pathways such as Wnt, NOTCH, PI3K, TGFβ, and more. We also explored associations between CK2 subunit expression and GI cancer clinical characteristics, of which we report the following significant findings (p < 0.05 for all). In colorectal adenocarcinoma, increased CSNK2A2 expression was associated with lymph node invasion and advanced clinical stage. In hepatocellular carcinoma, increased CSNK2A1 and CSNK2A3 expression was associated with greater tumor grade, tumor size, and more advanced clinical staging. Increased CSNK2A2 expression was associated with greater tumor size, more advanced clinical staging, and vascular invasion. Increased CS2NKB expression was associated with increased tumor grade, size, and vascular invasion. In pancreatic adenocarcinoma, increased CSNK2A3 expression was associated with a worse response to the first treatment course. Conclusions: Our results suggest that changes in protein kinase CK2 expression are associated with different cancer clinical characteristics as well as cancer-specific mutations and signaling pathways.