Whereas, in type 2 EC tumours are defined in this classification system as having TP53 mutations, a high Ki-67 (MIB1) score (a marker of proliferation), tumour suppressor gene p16 inactivation, increased cadherin-1 gene (CDH1) expression and the amplification of human epidermal growth factor receptor 2 gene (HER2), which is associated with metastatic disease and tumour spread [67,68]. This evidence concerns the gene ERBB2 and neoplasm.