Histopathological Characteristics of Triple-Negative Breast Cancer: An Iranian Issue

Background: Breast cancer is one of the most frequent malignancies among Iranian women. Triple-negative breast cancer (TNBC) is referred to a type of breast cancer which three biomarkers of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (HER2), are negative. Materials and Methods: In this case control study, immunohistopathologic data of patients with TNBC were compared with non-TNBC patients. According to pathological reports, frequency, age, gender, type, size, and tumor grade, involvement and the number of involved lymph nodes, mitosis, Ki-67, necrosis, nuclear grade, tumor side, involvement of the margins, skin involvement, nipple involvement, tumor location, vascular invasion, perineural invasion, presence of in-situ compartment and the benign accompanied tumors, granulomatosis reaction, and calcification were compared between both groups. Results: Two hundred fourteen pathological samples of patients with breast cancer were evaluated. TNBC was seen in about 14% of breast cancers in this study on Iranian population. The mean age of TNBC group was 43±12 years and non-TNBC was 50±12 years (p=0.03). TNBC had significantly higher grade, high mitotic indices, more possibility of P53 positivity and higher level of Ki-67. Presence of vascular and nerve invasion and involvement of the margins at the time of diagnosis were seen in the TNBC group comparing with the non-TNBC group. Conclusion: Younger age, higher grading, neurovascular invasion, P53 positivity, and high levels of Ki-67, lead clinicians to evaluate the biomarkers of TNBC, and in case of confirming TNBC diagnosis, appropriate treatment methods should be added to the routine ones in breast cancer.