Interestingly, the overexpression of NCAPHErBb2 in the mammary tissue of mice (MMTV‐NCAPHErBb2) developed significantly more tumours than their MMTV‐ErbB2 counterparts (Figure 3F,G), although no differences were observed in any other pathophenotypes of this disease. This evidence concerns the gene ERBB2 and neoplasm.