KMT5A and breast cancer: The widely used substrate‐competitive inhibitor of SETD8, UNC0379, with an in vitro IC50 value of 7.3 μm, may exhibit off‐target effects due to its shared quinazoline core structure with high‐potency inhibitors of G9a and GLP.[14] Therefore, further research is warranted to develop more effective therapeutic strategies targeting the SETD8/MYC axis in BC.