Therefore, to investigate the effect of CD10 in OGP‐free conditions, tumor cells and CAFs were cocultured in a culture medium lacking both serum and bovine serum albumin.[52, 53, 54] No appreciable difference was observed in mammosphere formation and chemotherapy‐induced apoptosis between tumor cells cultured alone and those cocultured with CD10+GPR77+‐depleted CAFs with CD10 forced expression (Figure S4G,H, Supporting Information). Here, ALB is linked to neoplasm.