For example, in order to study the underlying mechanisms why BRAF mutations are co-related with aggressive, less-differentiated, and therapy-resistant colorectal carcinoma clinically, Ricarda Herr et al. established a CDX mouse model based on human colorectal cancer cell lines whose B-RafV600E expression can be conditionally knocked down by doxycycline treatment, through which they revealed a novel facet of clinically applied B-Raf or MEK inhibitors by promoting cellular adhesion and differentiation of colorectal carcinoma cells (26). The gene discussed is MAP2K7; the disease is colorectal carcinoma.