In this presentation, I will focus on AFM study of mechanics of human epithelial cell and their change with aging and with malignancy. Recently we have found a considerable increase in rigidity of human epithelial cells while their ageing in-vitro. This is important because the loss in elasticity of epithelial tissues with ageing is associated with many human diseases. It was also shown that the cells had three distinctive regions of different rigidity. Developing a novel high resolution method to study cytoskeleton, we found correlation between the cell rigidity and the density of microfilament cytoskeletal fibres. Furthermore, using drugs that inhibit polymerization of microfilament, we restored the cell rigidities of old cells back to the young level in all three areas of rigidity simultaneously while preserving cells vitality. Some preliminary data of such treatment applied to aging skin of mice will be presented. The second example is about new things that can be learned with AFM about cancer cells. Mechanics of such cells is still in controversy. Studying cervical cell, we found that physics of mechanical properties of these cells is more complicated than scientists thought before. I will demonstrate that the surface of cancer cells is covered by molecules that are mechanically rather different from those of normal cells. Based on these measurements we developed a method for easy identification of cancer cells using fluorescent silica particles. This is still ongoing research aiming at developing a method for fast screening of precancerous epithelial tissue without biopsy.