differentiation

differentiation 1 The process by which cells become progressively more specialized; a normal process by which cells mature. Cells early in development have the potential to develop into many different types of tissues of the body. Differentiation occurs so the specific body tissues can form. Once developed into a specific cell type, the cell has lost its ability to differentiate into a cell for a different tissue. 2 In cancer, the difference in the maturity (development) of the cancer cells in a tumor. Differentiated tumor cells resemble normal cells and tend to grow and spread at a slower rate than undifferentiated or poorly differentiated tumor cells, which lack the structure and function of normal cells and grow uncontrollably. 3 The evolution from an incomplete form of disease to a complete form of disease.