Migrant women were more often diagnosed with a tumor with less favorable characteristics than autochthonous women; i.e., lymph node involvement (27.6% vs. 17.8%, p < 0.001), grade 3 (42.3% vs. 31.5%, p < 0.001), ER-negative (22.1% vs. 16.3%, p = 0.011), and HER2-positive (18.9% vs. 11.7%, p = 0.002). This evidence concerns the gene ERBB2 and neoplasm.