differentiation

Definition of differentiation
National Cancer Institute

differentiation

(DIH-feh-REN-shee-AY-shun)
In biology, describes the processes by which immature cells become mature cells with specific functions. In cancer, this describes how much or how little tumor tissue looks like the normal tissue it came from. Well-differentiated cancer cells look more like normal cells and tend to grow and spread more slowly than poorly differentiated or undifferentiated cancer cells. Differentiation is used in tumor grading systems, which are different for each type of cancer.

Source: NCI Dictionary of Cancer Terms