SPOCK1 and nonpapillary renal cell carcinoma: Our present results showed downregulation of MMP-2, -3, and -9 in SPOCK1-depleted Caki-1 cells, but only MMP-2 downregulation was observed in SPOCK1-depleted 786-O cells, suggesting that targeting of MMP-2 by SPOCK1 might be a general phenomenon in ccRCC cells.