TP53 and cholangiocarcinoma: ,34 Among these agents, CBD has emerged as a notable candidate known for its ability to arrest the cell cycle by upregulating the expression of p53 and p21 in solid and liquid tumors.34, 35, 36, 37 Consistent with previous research, our study showed that CBD treatment induces G1 cell cycle arrest in CCA cells, mediated in part by upregulation of p53 and p21 expression.