Tumour remission is accompanied by dephosphorylation of ERK1/2 and AKT/PKB, a strong decrease of Ki-67-positive nuclei in tumour tissue and a moderate increase in apoptosis as evidenced by the cytoplasmic fraction of cytochrome c. These data demonstrate a strong ERBB2 dependence of the tumours in our mouse model. This evidence concerns the gene MAPK3 and neoplasm.