Thus, the downregulation of p53 in OS with wild-type p53 may lead to the lower expression of Dkk-1, while Dkk-1 may be increased in a p53-independent manner for OS initiation and maintenance when p53 mutant occurs, which is similar to the regulatory mechanism between p53 and p21 in cancer [34]. The gene discussed is DKK1; the disease is cancer.