In this study, we demonstrated that anti-MUC1 IgG, IgM, and IgA antibodies could be detected in NAF using ELISA and that high level of anti-MUC1 IgG antibody in NAF was significantly associated with triple negative tumor phenotype (ER−, PR−, and Her 2−) and anti-MUC1 IgA antibodies were also significantly higher in the NAF of patients with LVI and Her2-neu-positive disease. The gene discussed is ESR1; the disease is neoplasm.