FOXA1 and extramammary Paget disease: FOXA1 was found to be strongly expressed in the nuclei of Paget cells in all the examined cases of EMPD (UPN1–UPN48 except for UPN39), regardless of the mutational status of the FOXA1 promoter or the presence or absence of the GAS6–FOXA1 fusion gene (Figure 4E,H,K).