Pharmacodynamic Study With FLT-PET/CT in Patients With Prostate/Other Solid Malignancies Treated With High Dose Axitinib

Inclusion Criteria: * Patients must have histologically or cytologically confirmed solid malignancy (excluding lymphoma) that is metastatic or unresectable and for which no standard therapy exists. * Patients must have measurable disease * Must be \>/= 18 years of age * All patients need to be willing to undergo planned pharmacodynamic assessments, including serial PET imaging, plasma markers, and pharmacokinetic sampling. Exclusion Criteria: * Patients who have had chemotherapy, radiotherapy, experimental therapy or major surgery within 4 weeks (6 weeks for nitrosoureas or mitomycin C) prior to entering the study or those who have not recovered (to grade -Patients may not be receiving any other investigational agents. * Patients with prior anti-VEGF directed therapy may be allowed only if approved by the PI and greater than 8 weeks since last exposure * History of allergic reactions attributed to compounds of similar chemical or biologic composition to axitinib * Patients with poorly controlled hypertension * Patients who require use of therapeutic doses of coumarin-derivative anticoagulants * Patients with any condition that impairs their ability to swallow and retain axitinib tablets are excluded. * Patients with any of the following conditions are excluded: Serious or nonhealing wound, ulcer, or bone fracture; History of abdominal fistula, gastrointestinal perforation, or intra-abdominal abscess within 28 days of treatment; Any history of cerebrovascular accident (CVA) or transient ischemic attack within 12 months prior to study entry; History of myocardial infarction, cardiac arrhythmia, stable/unstable angina, symptomatic congestive heart failure, or coronary/peripheral artery bypass graft or stenting within 12 months prior to study entry; History of pulmonary embolism within the past 12 months; Class III or IV heart failure as defined by the NYHA functional classification system. * Patients without appropriate lesion on CT scan for FLT-PET/CT imaging * CYP3A4 inducers/inhibitors medications will be reviewed by the Principal Investigator. * Steroid use is not recommended during axitinib treatment * Patients with a pre-existing thyroid abnormality who are unable to maintain thyroid function in the normal range with medication are ineligible. * Patients with known brain metastases should be excluded * HIV-positive patients on combination antiretroviral therapy are ineligible