**2.2 Free radical cause peroxynitrites**

Peroxynitrites (ONOO▬) could able to cause DNA strand breaks and oxidize cellular thiol groups in viable rat thymocytes in a dose-dependent fashion [32]. ONOO▬ is actively involved in the disturbances of signaling pathways of epidermal growth factors indirectly induced the process of tumorigenesis [33]. The combined effects of nitric oxide and oxidized LDL forms increase the concentrations of peroxynitrites that leads to glutathionylation of p21 ras proteins which results in aberrant activation of p21 [34]. The S-nitrosylation of PTEN, Bcl2 enhanced DNA mutation, and inhibition of apoptosis results in cell proliferation and cell survival [35]. The peroxynitrite could modify the DNA and increase the DNA adducts which act as antigens is one of the factors for the autoantibody induction in cancer patients [36]. Levels of peroxynitrite and nitrosylhemoglobin can be used as highly informative markers of disease prognosis and therapeutic approach [37].
