Indeed, SATIII is hypomethylated and over‐transcribed in several cancers and can be induced by 5‐azacytidine in HeLa cells.18 However, functional loss of DNMT in other cell types does not induce SATIII, suggesting multilayered regulation.24 To study the interplay of 5mC and HSF1 at individual SATIII loci of single cells, we combined TALE‐imaging with HSF1 immunostainings of U2OS bone cancer cells that exhibit strong HSF1 recruitment upon heat shock (Figure 4 b). Here, HSF1 is linked to bone cancer.