Hormone receptor status may vary: Walsh et al. [22] observed that most dMMR breast carcinomas from LS patients were hormone receptor negative compared to the pMMR subgroup, whereas the majority of LS breast carcinomas from our series were estrogen receptor-positive (15/18, 83%) and no difference between the dMMR and pMMR subgroups was observed. This evidence concerns the gene ESR1 and Leigh syndrome.