The tumor microenvironment plays an important role in cancer development and progression. Clinical studies have revealed that the increased T regulatory cells (Treg), high ratios of CD4/CD8 T lymphocytes, and extra follicular B cells in primary tumors correlated with worse overall survival [43-45]. Recently, studies from preclinical models have shown that tumor associated macrophages (TAM) can promote pulmonary metastases in breast cancer animal models, and in both the preclinical and clinical settings are associated with worse clinical outcome [46-48]. TGFβ has been linked to hormonal resistance in breast cancer. The activation of TGFβ leads to increased regulatory CD4+ T cells and decreased cytotoxic CD8+ T cells in the tumor microenvironment [49]. A recent study in non-small cell lung cancer suggests that baseline and post-treatment levels of cytokines, particularly IL-4 and IL-12 correlated with response to pazopanib[50]. In this study, the investigators will collect patient's serum to monitor the level of cytokines at baseline and during treatment, the investigators will compare the change of cytokine level with pazopanib in each patient, and also compare between responders and non-responders. This information may help us to identify biomarkers that would predict response to antiangiogenic therapy and to identify possible mechanisms of resistance.