Among the siCD81-upregulated genes, SEMA7A, a glycosylphosphatidylinositol membrane anchor promoting osteoclast and blood cell differentiation (Delorme et al., 2005; Jaimes et al., 2012), was depleted in CD81KO cells and siSEMA7a partially rescued or restored mammosphere formation in these cells (Figure 2—figure supplement 1D,F), suggesting a role of SEMA7A in inhibiting self-renewal of breast cancer cells. Here, SEMA7A is linked to breast carcinoma.