Comparative Bioinformatical Analysis of Pancreatic Head Cancer and Pancreatic Body/Tail Cancer

Abstract

The clinical differences between pancreatic head cancer and pancreatic body/tail cancer have been noticed for a long time. This study is to explore the biological disparities between these two from a bioinformatical perspective. Methods: RNA-seq, mutation and clinical data were downloaded and collected from The Cancer Genome Atlas (TCGA), FireHose and CBioPortal. The patients were divided into 146 cases of pancreatic head cancer and 28 cases of pancreatic body/tail cancer. Then survival analysis was performed. DEGs were screened by R package Deseq2. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and protein-protein interaction (PPI) were then carried out by DAVID and String. R package maftools and GenVisR were applied to analyze frequently-mutated genes and mutant-allele tumor heterogeneity (MATH) of PDAC. Results: Survival of patients with pancreatic body/tail cancer was better than those with pancreatic head cancer (median survival, 24.05 vs 19.45 months, p= 0.048). And 496 significant DEGs were identified including 253 downregulated genes and 243 up-regulated genes. And there were 13 Go terms (4 biological processes, 6 cellular components and 3 molecular functions) and 3 KEGG pathways (Pancreatic secretion, Fat digestion and absorption, Protein digestion and absorption) (FDR< 0.05). MATH scores of pancreatic body/tail cancer were higher than pancreatic head cancer, while chi-square test of top 10 frequentlymutated genes showed little difference between them. Conclusion: There were prognostic and genetic differences between pancreatic head cancer and pancreatic body/tail cancer. PDAC originated from different location may have different biological natures and should be considered with different management.