STIP1 and neoplasm: In our previous study, we obtained the enriched bone-seeking RCC cell line OS-RC-2-BM5 from in vivo selection [12], and here we detected a remarkably high expression of STIP1 on the cell surface membrane which also led to the secretion of STIP1 protein into the culture medium, indicating a possible autocrine effect of STIP1 on the bone-seeking tumor cell itself.