When LLPS mutants have been introduced in recent studies, they have been quite extensive, such as mutating all serines to alanine in the serine‐rich IDR of MED1 [23], or the change of a total of 17 acidic residues in the tAD of OCT4 [6], or changing either 12 or all 37 tyrosines in the prion‐like domain of the Ewing sarcoma fusion protein EWS‐FLI1 [57]. Here, POU5F1 is linked to Ewing sarcoma.