PCNA and colorectal carcinoma: In accordance with previous studies, WB analysis showed a prominently increased p-p38 level and a decreased p-ERK level caused by PLK4 depletion, and PLK4-depleted dormant-phenotype CRC cells alleviated the expression of important indicators of cell proliferation and cell cycle status, such as PCNA, CDK4 and CDK6 (Figure 1C).