Specifically, we validated the function of the protein STIP1 in promoting RCC tumor cell proliferation and migration/invasion through the autocrine STIP1-ALK2-SMAD1/5 pathway; and enhancing osteoclast differentiation and proliferation through the paracrine STIP1-PrPc-ERK1/2 pathway 4. This evidence concerns the gene STIP1 and renal cell carcinoma.