BRD4 and neoplasm: Moreover, to further confirm the influence of MZ1 on BRD4 expression in tumor tissues in vivo, our analysis using RT-qPCR and Western blot showed that, in contrast to the control group, MZ1 treatment significantly decreased the protein levels of BRD4 and also lowered the protein levels of the proliferation marker PCNA in tumor tissues (Fig. 5g).