In parallel, the levels of cyclin B1 and p-Histone H3 (Ser10) were also elevated in plumbagin-treated ESCC cells (Fig. 5c), implying that plumbagin-mediated PLK1 downregulation prevents cyclin B1 degradation, which contributes to drug-induced mitotic arrest. Here, CCNB1 is linked to esophageal squamous cell carcinoma.