BRD7 and neoplasm: The demethylation system constructed based on CRISPR/dCas9 and lentiviral delivery technology, LentiCRISPRv2/dCas9‐TET1CD‐sgRNA (sgRNA1‐5), can activate BRD7 expression to varying degrees and inhibit the proliferation of tumour cells, with sgRNA2 and sgRNA5 showing the most significant effects.