Figure 3. Regression of ear tumors by EGFR inhibitors.

(A-D) Assessment of ear tumor regression by MRI scan before and after treatment with EGFR inhibitors. SP-C/mEGFR^L+T mice with head tilt were randomized to 4 groups (3 mice/group) and then treated with cetuximab for 7 days (A), cetuximab combined with erlotinib or afatinib for 7 days (B and C), and WZ4002 for 5 days (D) as described dosing and schedule in Materials and Methods. See also Table S1. White ovals indicate dense areas of ear tumors. L, left side. Columns, mean of relative ear tumor volume from 3 mice in before and after treatment with each regimen. bars, standard deviation. Statistical analysis was performed with unpaired t test. P values of less than 0.05 were considered significant. (E) Change of tumor volume from baseline by EGFR inhibitors for individual SP-C/mEGFR^L+T mice bearing ear tumors in Table S1. CR, complete response; PR, partial response; SD, stable disease; PD, progressive disease. See also the criteria to classify tumor responses to drug treatment as described in Supplementary Materials and Methods.