Using the reads mapping to the transcript encoding for the reporter (dsRED) we selectively identified the tumor cells (Fig. 2a and Supplementary Fig. 2a), which we found to express a mesenchymal signature of transcripts encoding for extracellular matrix genes and collagens (Col1a1, Col1a2, Cald1, Calu). Here, COL1A2 is linked to neoplasm.