In human osteosarcoma, paired box gene 3 upregulates PAK2 expression and promotes the migration and differentiation of tumor cells by binding to the promoter region of the PAK2 gene.[91] Similarly, long‐chain fatty acyl‐CoA ligase 4 facilitates the binding of Sp1 to the PAK2 promoter, thereby increasing PAK2 transcription, which contributes to malignant progression in hepatocellular carcinoma.[92] Here, we demonstrate that MTA metabolic dysregulation leads to a reduction in H3K79me1 levels on the PAK2 promoter, which is implicated in the progression of Cd‐exposed BC. The gene discussed is PAK2; the disease is breast cancer.