OPN1SW and leukemia: Indeed, the mean CGI shore methylation of H1‐0, comprising probes cg07141002 and cg01883777, inversely correlated with H1‐0 expression (Pearson r = −0.645, p < 0.0001; Figures 4C and S9B) and was lowest in ETV6::RUNX1+ BCP‐ALL (Figure 4D), indicating that H1‐0 expression is regulated via dynamic methylation of its CGI shore in leukemia.