CD81 and cancer: Notably, a transmembrane ubiquitin ligase family member MARCH8 has been associated with lysosome degradation of both CD44 and CD81 in fibroblast cells (Bartee et al., 2010) and/or TNBC cells (Chen et al., 2021), suggesting CD44 and CD81 might follow similar fates of protein degradation or recycling in both cancer cells and other cells.