الفهرس 
Title pageOnly 14 pages are availabe for public view
 |  | from | 16 |  |  |
| | | from | 16 | | |
Abstract
Background: Triple Negative Breast Cancer (TNBC) is defined by a lack of expression of the steroid hormone receptors (oestrogen and progesterone), and the human epidermal growth factor receptor-2 (HER-2). It is characterized by distinct molecular, histological and clinical features and lacks the benefit of target specific therapy (75).
Basal-like breast cancer (BLBC) is associated with aggressive characteristics including development of recurrent disease and reduced survival. BLBC has been defined in some studies as tumours lacking both oestrogen receptor and progesterone receptor protein expression and associated with expression of basal-type cytokeratins, the phenotypic patterns of basal cytokeratin expression in BLBC have not been widely studied(84)
Aim: The present work aims to determine the expression of basal cytokeratin 5 and cytokeratin 17 in cases of triple negative breast carcinoma and correlate the expression of these basal cytokeratins with other prognostic parameters of breast cancer such as age, tumor size, histologic grade, lymph node metastasis and vascular invasion.
Materials and methods: the immunohistochemical expression of ck5 & ck17 was studied in 50 triple negative breast cancer cases.
Results: The patients with triple-negative breast cancer were younger, with the adverse pathological characteristics of a high tumour grade, tumour necrosis, frequent nodal metastases. Forty four cases (88%) of the 50 triple-negative breast carcinomas showed the expression of the basal markers (CK5 and /or CK17). Four different clusters of basal cytokeratin expression patterns were identified: (1) (CK5+/CK17+), (2) (CK5+/CK17-), (3) (CK5-/CK17+) and (4) (CK5-/CK17+). These patterns of basal cytokeratin expression associated with differences in patient prognosis, clusters 3 and 4 showed better prognosis than cluster 1 and 2, with cluster 1 having the poorest prognosis.
Conclusion: The triple-negative breast cancers harbor adverse pathobiological features and the “Triple-negative” status cannot be used as a surrogate for the “basal marker expression”. Cytokeratin 5 is a more reliable marker than ck17 to identify BLBC, but the use of immunohistochemichal panel including both basal cytokeratins is more preferable in this regards. Cluster 3(ck5-/ck17+) showed the best prognosis among the four clusters of TN breast cancer.