BRD7 and neoplasm: These results confirm that the lentivirus stably expressing the LentiCRISPRv2‐dCas9‐TET1CD‐sgRNA2&5 demethylation system can effectively infect tumours, leading to the demethylation of the highly methylated CpG island region of the BRD7 promoter, consequently activating BRD7 expression at the transcriptional level and thus exerting anti‐tumour roles in vivo.