MiaPaCa2 cells grew as subcutaneous tumors in three groups of athymic mice (10 mice per group) for 8 weeks. In the last 4 weeks, the mice were treated with emodin, rhein, or vehicle, respectively. (A-C). A tumor whose host was treated with vehicle is used to show common histological features. (A). In the whole-section image (original magnification: 50x), white lines surround typical apoptotic regions and black lines surround central necrosis. (B). A region full of apoptosis (original magnification: 400x). (C). Central necrosis (original magnification: 400x). (D-F). Data shown in these panels are derived from all tumors. (D). Total section area and the section area that was occupied by healthy tissue. (E). Tumor volume. (F). Tumor weight. * P<0.05.