ERBB2 and ductal breast carcinoma in situ: In the current issue of JCMM, Wang et al. challenged the conventional model of multi-stage carcinogenesis of breast cancer and proposed that ‘The invasive cancers do not all come from the in situ carcinomas’, based on their analysis of Her-2 overexpression in achieved tissue specimen and, inconsistent incidence between DCIS and mammary tumours [6].