DSP and neoplasm: Thus, while loss of Dsp and impairment of desmosomal adhesion leads to the focal invasion observed in IC1 lesions, the development of the broadly invasive phenotype found in IC2 lesions evidently requires the concomitant loss of Cdh1. Indeed, the IC2 tumor lesions that normally develop in RT2 mice show a coordinated reduction in the expression of Cdh1 and multiple desmosomal components (Table 1, Figure 1, and Figure S2).