The immunohistochemical markers used in breast cancer cases allow the classification of tumors into four subtypes: luminal A (1), luminal B (2), HER2 positive (3), and triple-negative or basal-like (4). This study aimed to evaluate the histological and immunohistochemical profile of breast cancer patients from a referral hospital in the inland of the state of São Paulo and understand the particularities of the prognosis based on the tumor-node-metastasis staging. Methods: This retrospective observational epidemiological cohort study was carried out at Hospital Regional de Presidente Prudente, with the first half of 2020 as the time frame. The research target population was women diagnosed with breast cancer who underwent immunohistochemical examination. We excluded patients with breast carcinoma in situ and incomplete medical records, which made data analysis impossible. After classifying the cases into four molecular subtypes based on immunohistochemistry, identifying the histological grade, and verifying the pathological staging criteria, we gathered the data and addressed the pathological-prognostic staging to investigate the prognosis of each patient. Results: We analyzed 49 patients with a complete immunohistochemical profile. Among them, luminal A (44.9%) was the most prevalent molecular subtype, followed by luminal B (36.7%). The least prevalent subtypes were triple-negative (16.8%) and HER2 (2%). Pathological-prognostic staging was possible in 73.5% of cases. Conclusions: The molecular subtype is important for tumor evaluation and has direct implications for the staging of breast cancer patients.