In vitro screening of a panel of pancreatic cancer cell lines and immortalized pancreatic stellate cells (PS1) showed the PTX3 monomer (45 kDa) to be expressed and secreted predominantly by PSC (Fig. 3A–B) and the antibody specificity was confirmed upon PTX3 RNAi (Fig. 3C). Here, PTX3 is linked to familial pancreatic carcinoma.