RACK1 and esophageal squamous cell carcinoma: In the digestive system, high RACK1 expression is significantly associated with poor prognosis in oral squamous cell carcinoma (OSCC) (Liu et al., 2018), esophageal squamous cell carcinoma (ESCC) (Wang et al., 2015), and pancreatic cancer (PC) (Li et al., 2016); however, several studies have demonstrated that RACK1 acts as a tumor suppressor in gastric cancer (GC) (Chen et al., 2015; Yu et al., 2021), indicating that it may be an organ-specific tumor marker.