Background: Breast cancer is one of the most diverse and well-known diseases. It has various molecular subtypes, clinical behaviors, therapeutic responses, and patient outcomes. The absence of hormonal expression (ER&PR) and the lack of excessive human epidermal growth factor receptor 2 expression are the two characteristics that are often used to identify triple-negative breast cancer (HER2). E-Cadherin is a cell adhesion molecule that inhibits metastasis, invasion, and cell growth. A non-histone nuclear protein called Ki 67 is connected to tissue and cellular proliferation.

Aim of the work: to evaluate the pattern of expression of E-cadherin and Ki 67 in the studied triple-negative breast cancer cases and to find their correlation with various clinicopathological parameters.

Materials & Methods: This study was carried out on 60 cases of triple-negative breast cancer. Immunohistochemical staining using E-cadherin and Ki 67 antibodies was done for all cases to evaluate their pattern of expression.

Results: There was a significant statistical negative relation between E-cadherin expression in TNBC and pleomorphic lobular subtype and axillary lymph node metastasis. Also, there was a significant statistical relation between high Ki 67 index (P value < 0.05) and high-grade histological types of TNBC cases, age groups and cases from lower inner quadrant.

Conclusions: Decreased E-cadherin expression is related to positive nodal metastasis. High tumour grade was substantially correlated with high levels of Ki-67 expression.