Strong evidence that our findings are not “chance” observations is provided by the following observations: (i) cPSCs could be reliably identified in two separate mouse models of PC; (ii) cPSCs were identified using both immunohistochemistry and single-cell RNA sequencing; (iii) cPSC numbers were found to vary in a way that is consistent with their postulated pathophysiology; (iv) cPSCs were modulated by drugs which strongly inhibit metastatic disease (HGF/c-Met inhibition [8,9,10]); and (v) cPSCs tend to be more commonly found in mice with recurrent disease. Here, HGF is linked to metastatic neoplasm.