ERBB2 and breast cancer: In support of our hypothesis, we found that inhibition of ErbB2 by lapatinib destabilizes mutp53, independently of type p53 mutation, in both H/H;ErbB2 and Q/-ErbB2 cultured mouse MECs (Figure 1A, 1B, 1D) and Her2 positive human breast cancer cell line BT474 (E285K) (Figure 1C, 1E).