For example, robust models of mammary or lung tumorigenesis originate from the MMTV–Erbb2 transgenic cassette or through the induction of a specific Kras allele, respectively.70 Moreover, orthotopic models are also suitable because they closely resemble the natural tumorigenesis process.79 However, the use of autochthonous and orthotopic models is limited as the experimental handling is both time-consuming and cost-intensive (e.g. genetic manipulation, tumour development and tumour monitoring) when compared with transplantable tumours. The gene discussed is ERBB2; the disease is neoplasm.