Further analysis of TCGA pancreatic ductal adenocarcinoma data in GEPIA showed that, twenty-one of the identified prognostic genes (ITGB6, LAMC2, KRT7, SERPINB5, IGF2BP3, IL1RN, MPZL2, SFTA2, MET, LAMA3, ARNTL2, SLC2A1, LAMB3, COL17A1, EPSTI1, IL1RAP, AK4, ANXA2, S100A16, KRT19, and GPRC5A) were also correlated with the pathological stages of the disease, underlying their prognostic value for PDAC (Fig. 3). The gene discussed is AK4; the disease is pancreatic ductal adenocarcinoma.