Breast cancer is the most common malignancy among women and a leading cause of cancer-related deaths in the general population. On the other hand, both incidence and mortality rates decreased over the past 10-15 years (1). Different clinical courses observed in cancer patients during the same stage suggest that this disease has a heterogeneous nature. Breast cancer has been categorised into 5 subtypes based on gene expression techniques (luminal A, luminal B, basal-like, human epidermal growth factor (HER2)-overexpressing, and normal breast like) (2-5). Estrogen receptor (ER), progesterone receptor (PR), and HER2 receptors are negative in basallike tumours, as in the case of triple-negative (TN) tumours. Because anti-keratin antibodies, used to identify the basal-like phenotype, are not routinely analysed during daily practice, the terms TN and basal-like are often used interchangeably. This, however, is not precisely accurate. DNA analyses and