Tumor core biopsy Arm A: Performed at baseline, approximately 3 weekly after cycle 1 AC but before cycle 2 AC, and upon completion of 4 cycles of AC, for a total of 3 tumor core biopsies Arm B: Performed at baseline, after completing the first course of sunitinib and before cycle 1 AC, approximately 3 weekly after cycle 1 AC but before cycle 2 AC, and upon completion of 4 cycles of AC, for a total of 4 tumor core biopsies.