GADD45A and cervical squamous intraepithelial neoplasia: p38 is activated in response to various stress stimuli, including CIN induction, and can induce cell cycle arrest by several mechanisms, including the upregulation of CDK inhibitors, growth arrest and DNA damage inducible alpha (GADD45α), and cyclin D, as well as the downregulation of CDC25.333,356–358 Moreover, p38 can work side-by-side with p53 to limit the progression of cells with CIN.