CD9 and hepatocellular carcinoma: In addition, the overexpression of some miRNAs contributes to the metastasis of digestive system tumor cell and poor prognosis via down-regulating Tspans’ transcription [for example, CD82 with miR-197 in hepatocellular carcinoma (Dai et al., 2014) and gastric cancer (Xu et al., 2017), CD82 with miR-362-3p in gastric cancer (Zhang et al., 2015), CD9 with miR-142-5p in gastric cancer (Zhao et al., 2020), Tspan9 with hsa-miR-9-5p in hepatocellular carcinoma (Tan et al., 2022)].