PTGS2 and cancer: Among the cancer signal transduction pathway-related genes (Table S1), dual specificity phosphatase 1 (Dusp1) and COX-2 (also known as PTGS2) were significantly over-expressed (2.34-fold, Q value = 0.008 and 3.77-fold, Q value = 0.029, respectively) in the mesenchymal profile (A17 cells, A17 tumors, MSCs) with respect to all the epithelial lineages.