EGFR and neoplasm: To test if increased Egfr contributed to increased tumor number on the C57BL/6J background, intestinal-specific double mutants were generated by deletion of EGFR and ERBB3 in C57BL/6J-ApcMin/+ mice (ApcMin/+, Erbb3f/f, Egfrf/f, Tg(Vil1-Cre)) (Fig 5B and 5C).