Previous studies have demonstrated that EYA4 acts as a tumor suppressor gene in non-small cell lung cancer [30], colorectal cancer [31], hepatocellular carcinoma [32], esophageal squamous cell carcinoma [33] and pancreatic ductal adenocarcinoma [29], but the biological role of EYA4 in BC remains unknown. This evidence concerns the gene EYA4 and pancreatic ductal adenocarcinoma.