Similarly, Hüsemann et al. [26] showed that cancer cells can spread systematically from earliest epithelial alterations in HER-2 and PyMT transgenic mice and from ductal carcinoma in situ (DCIS) in women, thus providing additional evidence that supports the novel outlook on the onset of metastatic spreading and its parallel progression (evolution) during tumorigenesis. This evidence concerns the gene ERBB2 and ductal breast carcinoma in situ.