To further clarify that tumors are derived from PROCR+/EpCAM− cells and few of the tumor cells trans-differentiate into EpCAM+ cells, we generated a single cell-derived clone (D4) from PROCR+/EpCAM− cell population of KTB42-HRasG12V + SV40-T/t transformed cells by sorting PROCR+/EpCAM− cells using flow cytometry (Fig. S15d). This evidence concerns the gene EPCAM and neoplasm.