Given that the expression of both Dsp and Cdh1 was lost in IC2 lesions, the most invasive class of RT2 tumors, both in unmodified RT2 mice and in tamoxifen-treated RT2+; Pdx1-CreER+; DspFlox/Flox mice (Figure 1 and data not shown), we infer that loss of Dsp by itself is sufficient to promote the development of focally invasive tumors while the additional loss of Cdh1 is required to develop a more aggressive invasive tumor phenotype. This evidence concerns the gene PDX1 and neoplasm.