Basic Considerations on static DNA Cytometry

Abstract

Static DNA cytometry is one of the few quantitative techniques, which have been successfully applied for diagnostic pathology. Having introduced and defined minimum requirements for this technique, it plays now-a-days a significant role in confirming or ruling out malignant tumours of various origins. In this article, some basic aspects of this technique are described. The following prerequisites are used: a) all nuclei of “normal” human cells which display the same position within the cell cycle contain the same amount of DNA; b) all human cells repeat the cell cycle with the same velocity; c) the cell cycle can roughly be divided into threeseparated stages, namely resting cells (G0), multiplication stage (S-phase), and reorganization stage (mitosis, doubled DNA content); d) cells undergoing degradation or apoptosis are negligible for reference cells. By use of these prerequisites, the following parameters can be derived: a) the number of reference cells at a cell cycle stage I (1,2,3) is proportional to the duration of the cell cycle stage I; b) the cell cycle stage I of the reference cells can be calculated from the absolute DNA content and the frequency distribution of the cell cycle stages (I-III); the absolute DNA content of reference cells can be computed from the frequency distribution of reference cells within the different cell cycles. For non-reference cells, similar derivatives hold true: a) the amount of additive/missing DNA in non-reference cells is proportional to the amount of DNA of reference cells measured at the same cell cycle stage; b) the additive/missing amount of DNA of non-reference cells can be derived from the DNA distribution of reference cells and that of non-reference cells. The significance of these derivatives for application of DNA cytometry is discussed.