The present invention relates to VEGF-binding agents, DLL4-binding agents, VEGF/DLL4 bispecific binding agents, and methods of using the agents for treating diseases such as cancer, particularly colorectal, ovarian (e.g., platinum-resistant ovarian), pancreatic, and endometrial cancers. Also provided are methods, compositions, and kits for treatment of tumors or cancer using combinations that include a VEGF/DLL4 bispecific agent and one or more chemotherapeutic agents (e.g., leucovorin, 5-fluorouracil, and irinotecan; paclitaxel; gemcitabine and ABRAXANE® (albumin-bound paclitaxel for injectable suspension); and paclitaxel and carboplatin). The present invention further provides methods of using the agents or combinations of agents to inhibit growth of a colorectal, ovarian, pancreatic, or endometrial tumor. Also described are methods of treating cancer, particularly colorectal, ovarian, pancreatic, and endometrial cancer, comprising administering a therapeutically effect amount of an agent, antibody, or therapeutic combination of the present invention to a patient having a tumor or cancer.