Serum phospho-CSE1L levels decline after sorafenib and lapatinib treatment in mice inoculated with human colorectal tumor xenografts. ELISA analysis of phospho-CSE1L levels in serum samples obtained from NOD SCID mice bearing HT-29 colorectal tumor xenografts and fed daily with 80 mg/kg of sorafenib plus 60 mg/kg of lapatinib or 1 mg/kg of lapatinib as the control for 10 days. Sera were collected from the mice 1 day prior to drug administration and 3 days after the first drug administration. The ELISA assays were performed two times and showed similar results. The data shown here are the representative results. The images in the lower panel are representative images of a mouse treated with sorafenib/lapatinib and showing tumor necrosis and a mouse from the control group 21 days after drug administration.