Inclusion Criteria:  Patients with a diagnosis of ductal cancer who enter the primary or neoadjuvant chemotherapy regimen treated with Doxorubicin or Cyclophosphamide. Patients with breast cancer with the HLA-A * 02: 01 haplotype. Women of legal age who are not pregnant or breastfeeding (patients or controls). Patients who have histologically confirmed primary breast carcinoma of the ductal type. Karnofsky index greater than 70% Voluntary acceptance of informed consent.  Exclusion Criteria:  Patients with a diagnosis of triple-negative breast cancer. Pregnant patients Patients under age or over 70 years Patients diagnosed with autoimmune diseases The patient has a Karnofsky lower than 70% or an ECOG higher than 1. Patients who have received some therapy as a treatment for their tumor pathology (radiotherapy, chemotherapy, immunotherapy, or gene therapy). Active autoimmune disease requiring treatment or a history of autoimmune disease that could be exacerbated by treatment. Patients with endocrine disease controlled by replacement therapy, including thyroid disease, adrenal disease, and vitiligo, can be included. Presence of a chronic or acute infection, such as HIV, viral hepatitis, or tuberculosis, before or after signing the informed consent. Use of immunosuppressants within 4 weeks before the trial (e.g., corticosteroids), such as azathioprine, prednisone, or cyclosporine A. The use of local steroids (topical, nasal, or inhaled) may be acceptable. Clinically significant cardiomyopathy, which requires treatment. Splenectomized patients. Patients who do not receive the neoadjuvant chemotherapy regimen with Doxorubicin and cyclophosphamide for three cycles or receive some other type of complementary therapy such as taxanes.