Abstract
Pancreatic ductal adenocarcinoma (PDAC) is among the most lethal cancers. Known risk factors for this disease are currently insufficient in predicting mortality. The only FDA approved prognostic biomarker for PDAC patients is CA19-9. This, along with AJCC TNM staging and performance status, are considered important prognostic indicators in clinical practice. In order to better prognosticate patients with PDAC, we identified a novel panel of genes by utilizing publically available microarray and RNAseq data of PDAC tumors from GEO and TCGA. Expression of 20 genes were significantly associated with overall survival in four datasets and event-free survival in TCGA. A score generated based on the expression matrix of these genes could be validated in two independent cohorts. We find that this “Pancreatic cancer prognostic score 20 – PPS20” is dramatically elevated in metastatic tissue compared to primary tumor, and is higher in primary tumors compared to normal pancreatic tissue. Transcriptomic analyses show that tumors with low PPS20 have overall more immune cell infiltration and a higher CD8 T cell/Treg ratio when compared to those with high PPS20. Analyses of proteomic data from TCGA PAAD indicated higher levels of Cyclin B1, RAD51, EGFR and a lower E-cadherin/Fibronectin ratio in tumors with high PPS20. The PPS20 score defines not only prognostic and biological sub-groups but can predict response to targeted therapy options as well. Overall, PPS20 is a stronger and more robust transcriptomic signature when compared to similar, previously published gene lists.
A novel 20-gene prognostic score in pancreatic adenocarcinoma
