**3. Aging and old age diseases**

In the aging process, functions of the p53 protein, *genome trader*, are impaired. The p53 protein does not lead to repair cells with damaged DNA or does not direct them to the path of apoptosis. The effect of these functional changes is increased susceptibility to infections, autoimmune diseases and cancers, including malignancies [1, 2]. The pathogenesis of tumors associated with the p53 protein is contained in this book.

In addition, older people often develop neurological diseases including Alzheimer's and Parkinson's diseases, epilepsy, and stroke. Based on the modern knowledge, it is difficult to separate normal and pathological aging, and neurodegeneration of central neurons. More information in the chapter, normal aging and neurodegenerative disorders.

The aging process is not limited to the central nervous system. It also includes other organs such as heart and liver. It is believed that the loss of liver regenerative capacity is disturbed in the elderly. Defective liver cells undergo apoptosis or aging. Aging cells are responsible for fibrosis and hepatocellular carcinoma. Is senescence important in hepatic diseases, available in this book.

Moreover, recently a growing interest focuses on senescent cells in the context of old age diseases, malignancy and insulin resistance, and as a therapeutic goal to prolong health.
