Enhanced plasma elimination of mAb, when bound to a soluble antigen, has been observed previously by our group, with co-administration of recombinant carcinoembryonic antigen (CEA) leading to a ∼2-fold increase in plasma elimination of the anti-CEA mAb T84.66, decreasing total tumor exposure of T84.66 in a CEA positive xenograft mouse model by 55% (Abuqayyas, 2012). This evidence concerns the gene CEACAM5 and neoplasm.