TSPAN8 and digestive system cancer: The expression of tetraspanin CO-029 is typically linked to poor prognosis of digestive system cancers [12], [16], [18], [46], [52], [53], CO-029 is upregulated upon the progression of colorectal, liver, pancreatic, and esophageal cancers [11], [46], [54], and the increased expression of CO-029 promotes the liver or lung metastasis of these cancers [17], [52], [53], [55].