Hello, I conducted mouse tumor digestion using two different protocols: one involving 0.1% trypsinization and the other using 0.4 mg/ml collagenase + 1.25 U/ml dispase II. The chopped tumor was kept at 37°C for 1 hour for enzymatic digestion (Enzymes in DMEM:F12 with no FBS no PS), followed by inactivation in advanced DMEM:F12, 10% FBS, 1% PS. I plated 9*10^5 cells, with 85% being live cells. However, in the next couple of days, I noticed that no cells were growing, and they seemed to be dying. Is this a normal outcome, or should all tumor cells be immortalized?