PTX3 binds C1q and activates or regulates the classic pathway, by interacting with M-ficolins and MBL can modulate the lectin pathway; moreover, at a soluble level, PTX3 interacts with Factor H. In prostate cancer and renal cell carcinoma, increased tissue and serum expression of PTX3 has been assessed and correlated with poor prognosis. This evidence concerns the gene PTX3 and renal cell carcinoma.