Summary Introduction: The role of sentinel node biopsy has revolutionized breast cancer treatment. This determinationreduces the mobility of a complete axillary lymphadenectomy. The aim of our study is to analyze the value of sentinelnode inlow-grade hsti ological breast tumors, studied with hematoxyin anl d eosin techniques, Immunohistochemistry,and molecular chain reaction in real-time quantitative polymerase (RT-PCR).Materials and methods: In a pilot study we studied a total of 21 patients with histological diagnosis of mucinouscarcinoma, adenoid cystic carcinoma, and medullar carcinoma that underwent the sentinel node technique. Once thelymph node was removed, it was sent to pathology, where it was fragmented and evaluated, using between 25% and50% of the lymph node for molecular biology laboratory studies.Results: The sentinel nodes studied were 32, corresponding to the 21 patients. Of the 32 lymph nodes analyzed,29 (90.6%) were negative on histopathological examination and the molecular identification, 2 (6.2%) were positivein both techniques and 1 (3.125%) lymph node was positive with quantitative RT-PCR and negative in histology(HE this can reduce the false negative andimprove diagnosis of sentinel node metastases. Patients with low histological grade carcinomas have high survivalrates, less aggressive tumor behavior, and reduced lymph node at diagnosis.Keywords: Lymphatic metastasis; Breast neoplasm; Polymerase chain reaction; Biopsy;Immunohistochemistry; Lymph node excision.