Polycyclic aromatic hydrocarbon carcinogens increase ubiquitination of p21 protein after the stabilization of p53 and the expression of p21. - Nakanishi Y; Pei XH; Takayama K; Bai F; Izumi M; Kimotsuki K; Inoue K; Minami T; Wataya H; Hara N (American journal of respiratory cell and molecular biology, 2000)