Oxaliplatin-DNA adducts can be measured in the PBMC and tumor of a breast cancer patient. (A) Schematic of diagnostic microdosing strategy. (B) A metastatic breast cancer patient was given a diagnostic microdose of oxaliplatin [1.3 mg/m2 (29.2 mg/kg) supplemented with 2 × 106 dpm/kg [14C]oxaliplatin] by a 2 min intravenous (IV) infusion in the peripheral vein of one arm. Peripheral blood was drawn from the other arm prior to and 5, 15, 30 min, 2, 4, 8, 24, and 48 h after the administration of the microdose and oxaliplatin concentration determined by LSC. (C) PBMC was isolated from the peripheral blood samples above, and the number of adducts determined by AMS. (D) DNA was isolated from a tumor biopsy collected 48 h after administration of the microdose and adducts determined by AMS. (E) DNA repair rates were determined in PBMC isolated from the blood samples collected at 4 h after microdose administration that were cultured in drug-free media for an additional 4 or 20 h.