In most mature tissue, most of the cells are diploid, with only a small percentage of cells actively synthesizing DNA (S for Synthesizing phase) and only a small percentage of cells in a pre-mitotic state with tetraploid nuclei (twice the normal diploid DNA content). In malignant tumors, both of these populations are present at much greater levels, reflecting the overall increased cellular mitotic activity. In addition, malignant tumors have aneuploid peaks for nuclei with an abnormal amount of nuclear DNA.
