in vitro , normal keratinocytes exhibit undifferentiated morphologic features and proliferate for multiple passages in low-calcium medium ( less than or equal to 0.3 mmol/l ) whereas , in high-calcium medium ( greater than or equal to 1.0 mmol/l ) , these cells assume differentiation characteristics , begin to stratify , and eventually cease proliferating .
C0007634
cells
C0007589
differentiation