Background: Triple-negative breast cancers (TNBC) are defined as breast cancers with lack of estrogen and progesterone receptors and no overexpression of human epidermal growth factor receptor 2 (HER2). This study was performed to determine the frequency and pathologic features of TNBC in Iranian patients. Subjects and Methods: This cross-sectional study was performed on patients with breast cancer who referred to Cancer Institute, affiliated to Tehran University of Medical Sciences, from April 2014 to April 2015. Data about the demographics, the status of gene receptors and the pathologic features were extracted from patients' records. Results: Of 214 pathology samples of patients with malignant breast cancer, TNBCs account for 14% of cases. The mean age in N-TNBC group was 50 ± 12 years. Significant difference was seen between the age of two groups (p=0.03). No significant difference was observed regarding the number of involved lymph nodes between two groups (p=0.058). Presence of vascular and nerve invasion and involvement of surgical margins at the time of diagnosis were significantly more frequent in TNBC group comparing with N-TNBC. Grade III of histologic and nuclear grading was significantly more common in TNBC. Conclusion: TNBC group was significantly associated with higher grade, higher mitotic indices and higher rate of P53 positivity and higher level of Ki-67 at the time of diagnosis. High grade breast cancers are more seen in TNBC. The presence of aforementioned characteristics in a patient highlights the need for evaluating TNBC biomarkers to better predict prognosis and consider appropriate treatment.
Keywords: Epidemiology; Iranian patients; Triple-negative breast cancer.