Figure 2.

Histology of kidney tumors and normal kidneys from mice treated with sunitinib and gemcitabine. Kidney tumors and normal contralateral kidneys from mice treated with sunitinib (20 mg/kg), gemcitabine (20 mg/kg), and both combined, obtained on day 28 from experiments described in Figure 1, were processed for histology and H&E staining. The main findings were labeled on the prints with T for tumor, V for vessels, G for giant tumor cells. (A) Kidney tumors. Control untreated tumors consisted of tumor cells with large pleomorphic nuclei were highly vascularized with a sinusoidal vascular pattern of abnormal enlarged dilated vessels with focal extravasation of RBCs. Sunitinib (SU)-treated tumors showed thinning and organization of tumor vessels as well as a decrease in the numbers of tumor vessels. Kidney tumors of mice treated with gemcitabine (Gem) contain numerous abnormal and giant tumor cells with cytoplasmic vacuoles or eosinophilic inclusions and degenerative changes in nuclei with focal karyopyknosis. Note some of the vessels in these tumors were still enlarged with foci of RBCs extravasation, however, to a lesser degree than in the untreated tumors. Tumors treated with sunitinib and gemcitabine (SU + Gem) consisted mostly of abnormal degenerating giant tumor cells. Trimming of tumor vessels was evident. (B) Normal contralateral left kidneys. The normal kidney from control mice showed intact, regular, and thin blood vessels. Sunitinib at 20 mg/kg showed a mild effect of dilatation in a few vessels. Gemcitabine caused dilatation of some of the blood vessels. This effect was milder with combined sunitinib and gemcitabine with fewer vessels dilated. All magnifications, x40.