Introduction: The EGF-TM7 subfamily of G-protein coupled receptors (GPCRs) are expressed mainly on leukocytes and believed to play a role in cell adhesion and migration. They have been detected in numerous epithelial cancers including gastric, esophageal, thyroid, pancreatic, and colorectal carcinomas. EMR2 and EMR3, members of the EGF-TM7 subfamily, have been detected in glioblastoma and shown to confer increased invasion in vitro and are associated with decreased survival using data from The Cancer Genome Atlas (TCGA). We report new data on CD97, another member of the EGF-TM7 subfamily, demonstrating its expression in glioblastoma (GBM) and an association with overall survival.
Methods: Using previously established culturing conditions, we isolated and expanded primary glioblastoma cells. RNA and protein were isolated from these cells and used for PCR and Western blot analysis.
Results: Kaplan-Meier analysis of TCGA data shows that upregulation of CD97 is associated with a significant decrease in overall survival. Primary GBM culture demonstrated variable protein expression, with evidence of isoforms at the transcript level. Additionally, a library of four established GBM cell lines also demonstrated variable expression.
Conclusions: CD97 is an adhesion molecule expressed in leukocytes and epithelial tumors. We present data that demonstrates expression in primary glioblastoma as well as a statistically significant association with overall survival. Given the growing body of literature implicating the EGF-TM7 family in tumor invasion and angiogenesis, CD97 may prove to be an important mediator of GBM dissemination.
Patient Care: Increase understanding of a potential mediator of GBM invasion
Learning Objectives: 1. Understand the importance of GBM dissemination
2. Recognize the potential significance of CD97 in GBM invasion