Translational study associated to a phase II study evaluating the activity of pazopanib in patients (pts) with advanced/metastatic liposarcoma (LPS): A joint Spanish Sarcoma Group (GEIS) and German Interdisciplinary Sarcoma Group (GISG) study.

11067 Background: GEIS 30 was a phase II study showing moderate activity of pazopanib in well-differentiated/dedifferentiated LPS (cohort A:37 pts, Progression free Survival (PFS) at 12 weeks (w) 43.2%) and no activity in Myxoid/round cell LPS (cohort B: 15 pts, PFS at 12w 13.3%). The present study aims to identify tumor and plasma biomarkers that are differently expressed in long responders (LRs) PFS > 24 w. Methods: Serum samples and paraffin-blocks at diagnosis were collected for 28 pts in cohort A and 11 in B. A total of 13 pts were LRs. Serum samples were obtained at baseline, after 3 w of treatment and at progression. A panel of 15 cytokines and growth factors were evaluated using…