Results obtained by RT-PCR (Figure 1) showed that MIG6 was mainly underexpressed in our breast tumor series (underexpression 45.0%, overexpression 5.5%; median mRNA level, 0.53; range, 0.00-5.93) and more particularly in the HR+/HER2- subtype (51.2%). Here, ERRFI1 is linked to breast neoplasm.