We first evaluated endogenous levels of SPOCK1 in a set of RCC cell lines including ccRCC (Caki-1 and 786-O) and pRCC (ACHN and Caki-2) cells by Western blotting and found that ccRCC cells expressed higher SPOCK1 levels compared to the pRCC cell lines (Figure 2A). This evidence concerns the gene SPOCK1 and nonpapillary renal cell carcinoma.