PaCa 5061 primary human pancreatic adenocarcinoma xenograft immunohistochemically stained with an anti-hyaluronan polyclonal antibody.

Note the staining of the cancer cells themselves, which were more intensively stained than the surrounding extracellular matrix (A). If hyaluronan was detected by hyaluronic acid binding protein, it was present in the extracellular matrix and not in the cancer cells themselves (C). If the section was pre-treated with hyaluronidase, the hyaluronan immunoreactivity did not vanish after antibody IHC (B); in contrast, hyaluronidase pre-treatment abolished its reactivity completely according to HABP staining (D). Collectively these results indicate that the anti-hyaluronan antibody binding is not caused by hyaluronan and that this approach is therefore unsuitable for its detection.