To explore the role of MCL‐1 in mouse skin and HFs, we employed a transgenic line expressing Cre recombinase under the control of a 5 Kb human Krt5 (K5) promoter to delete Mcl‐1 in all skin epithelial lineages, including HFs (Fig. S1E, F). This evidence concerns the gene KRT5 and Hand-foot syndrome.