Figure 6. huAR9.6 can delineate lymph node involvement in a xenograft model of ovarian cancer.

(A) PET-CT image of a mouse bearing a subcutaneous OVCAR3 xenograft acquired 6 d after the i.v. injection of 2.14 mg/kg [⁸⁹Zr]Zr-DFO-huAR9.6 (250 μCi; 9.25 MBq; 53 μg) showing uptake of radioactivity in the tumor (T), liver (L), and ipsilateral lymph node chain; (B) Pan-cytokeratin (Pan-CK) IHC staining of the OVCAR3 tumor showing a pattern of CK expression that is characteristic of epithelial cancer cells; (C-E) Pan-CK IHC staining of the PET-positive IALN showing (C) immunoreactive foci of neoplastic cells (red arrowheads) and lymphatic fluid (black arrows) in the subcapsular sinuses; (D) the cortex of the LN showing CK-positivity in star-shaped cells (green arrowheads) indicative of dendritic cells; and (E) a cluster of neoplastic cells infiltrating the IALN (red arrows) (E); (F) IHC staining of the OVCAR3 tumor with huAR9.6 showing membranous staining of the OVCAR3 cells; (G-I) huAR9.6 IHC staining of the PET-positive IALN (G) showing the presence of a few neoplastic cells (red arrowheads). The inset shows the appearance of the huAR9.6-stained PET-positive but H&E-negative IALN, and the red box in the inset identifies the portion shown in the main image; (H) the cortex and follicles of the LN showing positivity for huAR9.6 staining in star-shaped cells (yellow arrowheads) indicative of dendritic cells; and (I) a cluster of neoplastic cells draining into and infiltrating the medulla of the IALN (red arrows). The inset shows the architecture and appearance of the corresponding huAR9.6-stained PET-positive but H&E-negative IALN, and the red box in the inset identifies the portion shown in the main image.