RACK1 and esophageal squamous cell carcinoma: Recently, studies indicated that RACK1 plays a dramatic role in the occurrence, development, and metastasis of various cancers, including non-small-cell lung cancer [15–17], hepatocellular carcinoma [18, 19], esophageal squamous cell carcinoma [20, 21], breast cancer [22, 23], and prostate cancer [24, 25].