TGFB1 and papilloma: Consistent with this correlation, in utero co-injection of a TGFβ-signalling mCherrynuclear reporter and a Lepr-eGFPcytoplasmic reporter revealed that the highest double-fluorescence positivity was among invasive SCC, and the majority of total TGFβ-signalling cells in these regions were positive for the Lepr-eGFPcytoplasmic reporter in SCC in contrast to papilloma (Extended Data Fig. 5f).