IMMUNOPHENOTYPING OF BREAST CANCER ASSOCIATED WITH MALIGNANT TUMOR CLASSIFICATION AND HISTOPATHOLOGICAL FEATURES

Abstract

Objective: The immunohistochemical profile of breast cancer is based on the evaluation of estrogen and progesterone
receptors, HER2 expression, and cell proliferation index. An investigation of the association of immunophenotyping with
the classification of tumors and the description of their anatomical extent becomes important in view of the scarcity of
research in mixed populations such as the Brazilian. Thus, this research performed the association of immunophenotyping — luminal A, luminal B HER2-negative, luminal B HER2-positive, HER2-positive, and triple-negative — with the
classification of malignant tumors and histopathological characteristics in patients with breast cancer seen in a cancer
center in southeastern Brazil. Methods: This is a cross-sectional study with 583 female patients with invasive breast cancer in whom Pearson’s chi-square test or Fisher’s exact test was used for statistical analysis. Results: There was a higher
frequency of women with the luminal B HER2-negative subtype (33.9%). Analysis of immunophenotyping with clinical
characteristics found a higher frequency of clinical stage I in luminal A, 40% (p<0.001); pathological stage I in luminal A,
45% (p<0.001); invasive ductal carcinoma morphology in HER2-positive, 97.4% (p<0.001); histological grade G3 in triple-
-negative, 66.3% (p<0.001); nuclear grade 3 in HER2-positive, 87.2% (p<0.001); and e-cadherin positive in HER2-positive
luminal B, 81.8% (p<0.001). Conclusion: There was a significant rate of pathological primary tumor T0 in the triple-negative
(21.7%), which highlighted the advance of therapy in this subtype hitherto known to be of worse prognosis. Contrary to
expectations, the molecular subtype that showed the most metastasis was luminal B-positive (10.8%). We observed that
in the population analyzed, immunophenotyping showed an association with clinical and histopathological characteristics. The more severe molecular subtypes presented a more advanced stage.