A liability theory of disease: the foundation of cell population pathology

Within a homogeneous population of cells, the tendency of individual cells to become diseased is not 'homogeneous'. As a general concept of disease, the 'liability theory' describes such a tendency (cell liability) as a quantitative characteristic following a continuous distribution. This suggests that there are always some cells that are more liable than the rest and that the liability values of cells or liability-associated cell characteristics can be assessed quantitatively. By defining the more or extremely liable cells through a critical value or 'threshold', the liability theory hypothesizes that these cells may play a significant role in determining or affecting the overall disease liability of a cell population; the more such cells are present, the more liable the cell population is, as a whole, to disease. Furthermore, it proposes that the origin and development of disease may be fundamentally relevant to this kind of intrapopulational variation in cell liability. The liability theory attempts to provide a theoretical framework for studying the 'cell population' mechanism of disease, or cell population pathology. Also, it may serve as a working model for analysis and assessment of cell population liabilities for various diseases.