Brief Summary: Pazopanib is a new cancer drug that works by limiting the growth of new blood vessels in tumours. About half of patients who take pazopanib develop high blood pressure (hypertension). This side effect can make patients have to reduce or stop their cancer treatment, and can cause other health problems. The aim of this study is to find out exactly how the drug causes high blood pressure.

Detailed Description: For this study, up to 52 patients with different cancer types will take pazopanib tablets for 12 weeks. They will visit the clinic every 1-2 weeks during treatment, and for a final safety check 4 weeks after stopping the drug (10 visits over 18 weeks). At every visit, we will do a heart tracing, and check the patient's blood pressure and blood and urine chemicals (to check their health, and see if levels of these chemicals change). Patients will check their blood pressure at home every other day. They will also wear a blood pressure monitor for 24 hours on 3 occasions (during normal daily activities). Patients will have 1 or 2 CT scans and 3 MRI scans during the study. On three occasions, a variety of specialised tests will measure how the patient's blood vessels are working. Patients may choose to continue taking the drug after the 12 weeks of treatment, if their doctor feels it is appropriate. Understanding how pazopanib causes high blood pressure will help us to advise doctors how to treat the high blood pressure effectively, so that patients can continue to take their cancer treatment safely. This research might also lead to the development of new cancer drugs in future, which do not cause this serious side effect.