Several tetraspanins, including tetraspanin 8 (TSPAN8), are known to be overexpressed in various types of cancers and have been associated with a poor prognosis, whereas some tetraspanins are downregulated (e.g., TSPAN5 in gastric cancer and TSPAN30 in lung cancer) and inversely correlated with overall patient survival [12,13]. Here, TSPAN8 is linked to gastric cancer.