(a–c) Transverse color-coded US images of
subcutaneous human ovarian cancer xenograft (scale bar = 1 mm) imaged
longitudinally after intravenous administration of MBEndoglin
in the same mouse at three tumor stages (a, small;
b, medium; c, large). Note that targeted
contrast-enhanced US imaging signal (shown as green areas overlaid on
B-mode images) was highest in small tumors and decreased as tumors grew
larger. (d) Representative immunoblots of ovarian cancer
lysates from small, medium, and large tumors show decreasing expression
levels as tumors grow larger (upper row). α Tubulin was used
as a loading control (lower row).