Immunohistochemical profile and clinical-pathological variants of breast cancer in Northeastern Mexico

Background: Breast cancer is a heterogeneous illness, with subtypes of varying etiology. Estrogen Receptor (ER), Progesterone Receptor (PR) and HER2/neu (Human Epidermal Growth Factor Receptor 2) expressions have been identified as predicting factors. Objective: To demonstrate the possible association of the five immunohistochemical (IHC) expression profiles with clinical and histopathological variables of breast cancer in northeastern Mexico. Methodology: In 522 women with breast carcinoma, five IHC profiles were defined [Luminal A, Luminal B, Mixed, HER2/neu and Triple-negative (TN)]. An analysis was done to determine if there were differences between them in relation to the clinical and histopathological variables. Results: The distribution of the histological subtypes was: luminal A (32.97%), TN (27.53%), HER2/neu (19.02%), mixed (13.41%) and luminal B (7.07%). The average age at diagnosis was 53.07 ± 12.08 years, in 90.5% of the patients the size of the tumor was ≥ 2.0 cm, and 40.94% had lymph node involvement. Luminal A subtype had the highest percentage in the postmenopausal state (63.7%, p=0.071). Illness recurred in 21.01% of the patients (n=116), principally with the TN subtype (28.3%, p=0.012). Conclusions: This study detected the characterization of IHC subgroups in patients treated for breast cancer at a reference center for cancer treatment in northeastern Mexico.