In renal cell carcinoma, down-regulation of CXXC4 by siRNA resulted in the up-regulation of some cellular proliferation related genes (FGF18, EGR1, and MYCN), the down-regulation of apoptosis inhibitor proteins BIRC7 and XAF1, and some other important tumor progression factors [14]. This evidence concerns the gene FGF18 and hereditary clear cell renal cell carcinoma.