TP53 and neoplasm: However, it has also been reported that p21 binds to the central domain of HDM2 (Jin et al, 2003; Zhang et al, 2004), where RPL11 also binds (Zheng et al, 2015), and that HDM2 promotes the degradation of p21 in tumor cells which are either deficient or mutated in p53 (Jin et al, 2003; Zhang et al, 2004).