MAPK1 and liver cancer: Based on TCGA database, we analyzed the ERK2 (MAPK1) expression in liver cancer and its relationship with the overall survival of liver cancer patients, and the results revealed that ERK2 (MAPK1) was highly expressed in clinical tissue samples of liver cancer patients (Fig. 4A) and that ERK2 (MAPK1) expression was negatively correlated with the overall survival of patients (Fig. 4B, Additional file 2: Figure S3A).