This is an open-label, four-arm, Phase I, dose escalation study to evaluate the safety and tolerability and to determine the optimal tolerated regimen (OTR) of pazopanib in combination with epirubicin or doxorubicin in patients with advanced solid tumors. Patients will be enrolled in cohorts of 3 to receive escalating doses of pazopanib and epirubicin or doxorubicin. Dose escalation schemas for each study arm are described in the protocol. For each arm, the OTR will be defined as the highest dose combination of the agents where no more than one out of six patients experiences a dose-limiting toxicity. Twelve additional patients in each arm will be studied with the OTR to evaluate toxicity and pharmacokinetics. This will allow an assessment of potential drug-drug interactions. Antitumor activity will be assessed using RECIST criteria.