Predictive Value of Drug Elimination Gene Polymorphisms on Clearance and Dose Adjustment of Sunitinib in Cancer Patients

Inclusion Criteria: * Age \>18 * A malignancy treated with single agent sunitinib * ECOG 0, 1 or 2 at time of study accruement * Any stable dose of therapy with sunitinib (defined as no dose change within 3 weeks prior to blood collection for pharmacokinetics) * Adequate liver and renal function defined as serum bilirubin concentration less than 2 x ULN, AST and ALT less than 2.5 x ULN, serum creatinine concentration less than 2 x ULN * No known primary liver disease and no other severe or uncontrolled concurrent medical condition within the first 3 months of treatment with sunitinib. * Patients who have participated on other clinical studies of sunitinib will be suitable for this study. * Signed informed consent * Patients must not have Class ¾ cardiac problems as defined by the New York Heart Association criteria or any other severe or uncontrolled concurrent medical disease. * Patients must not be pregnant or nursing and must be using an effective contraception method Exclusion Criteria: * Patients who are unable to sign informed consent * Patients unable to give blood * Patients with known midazolam allergies will not be included * Patients must not be pregnant or nursing and must be using an effective contraception method * Patients who had a bone-marrow-transplantation prior to sunitinib treatment * Patients must not be taking routine systemic corticoid therapy * Patients must not be taking therapeutic warfarin or warfarin derivates doses as anticoagulation at the time of study tests with an at least 2 weeks warfarin free period of time prior. Patients requiring anticoagulation may use low-molecular weight heparin