DNMT3B‐mediated radioresistance was reported in various cancers, however, the mechanisms were heterogeneous.[35, 36] The present study was the first to identify DUSP2 as a downstream gene of DNMT3B‐L and further demonstrated that DNMT3B‐L could increase the methylation of the DUSP2 promoter, thereby inhibiting DUSP2 expression. The gene discussed is DUSP2; the disease is cancer.