Coadministration of testicular bovine hyaluronidase enhances spread and antitumor activity of ICOVIR5. (a) SkMel-28 s.c. tumor xenografts were treated intratumorally with PBS, testicular bovine hyaluronidase (PH20), ICOVIR5, or a combination of PH20 hyaluronidase and ICOVIR5. Tumor volume + SEM is plotted (n = 10). #Significant (P ≤ 0.01) compared with tumors treated with PBS; *Significant (P ≤ 0.01) compared with tumors treated with PH20 hyaluronidase. (b,c) Analysis of extracellular matrix and adenovirus distribution in melanoma tumors treated with ICOVIR5 or ICOVIR5, and hyaluronidase obtained 14 days after administration. (b) Deparaffinized tumor sections were stained for HA using the HABP-b and counterstained with hematoxylin. Upper panel: original magnification ×40. Lower panel: original magnification ×200. (c) Upper panel: adenovirus immunodetection was performed in frozen sections with an antiadenovirus antibody and counterstained with 4′,6′-diaminidino-2-phenylindole (DAPI); original magnification ×40. Lower panel: adenovirus immunodetection was performed in deparaffinized tumor sections with an antiadenovirus antibody and counterstained with hematoxylin; original magnification ×40. PBS, phosphate-buffered saline.