PLAUR and colorectal cancer: Because C4.4A, similar to uPAR expression (Mazumdar et al, 2001), has been described to become upregulated or induced by, for example, heat-labile serum factors (Seiter et al, 2001), expression of C4.4A on colorectal cancer lines was re-evaluated after cells had been cultured for 24 h in the presence of fresh AB0 serum.