Histopathological characteristics and immunohistochemical biomarkers of invasive breast cancer in Ethiopia women

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Date

2019-05

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Addis Abeba University

Abstract

Background: Breast cancer has been shown as commonest type of cancer in Ethiopian women. It is a heterogeneous disease in terms of clinical, histopathological and biological characteristics. Some of the molecular differences underlying this heterogeneity were previously discovered by genetic expression profiles and validated by immunohistochemical surrogates. Hence, this study was carried out to analyze breast cancer by histopathological features and immunohistochemical markers, and interrelationship among them in Ethiopian female breast cancer cases. Method: This study was a retrospective analytical study done on clinically and pathologically confirmed breast cancer cases that underwent modified radical mastectomy (MRM) from June, 2014 – June, 2015. The primary breast tumor tissues with the corresponding axillary lymph nodes were examined for histopathological features including histologic type, tumor size, nodal status and grade. Evaluation of the molecular markers including ER, PR, EGFR and VEGF-A were done by immunohistochemistry using formalin-fixed and paraffin-embeded tissues. Data was analyzed using SPSS 24.0. The p value <0.05 was set to be significant for all statistical tests. Result: The age range at diagnosis was 22-75 years (mean, 42.14±11.96) and more than 70% of the cases were below 50 years of age. The commonest histologic type was invasive ductal carcinoma (NOS, 89.2%). The frequency of pathologic tumor size was 11.3% for T1, 27.5% for T2, 32.5% for T3 and 28.8% for T4. Majority (74%) of them were lymph node positive. Half of the tumors were Grade III followed by grade II (38%). The IHC positivity for ER, PR, and EGFR were 73.8%, 60.2%, and 21.69% respectively. VEGF-A expression was negative, low, moderate and high in 13.41%, 63.41%, 20.73% and 2.44% of the tumors respectively. Significant associations were observed between age and tumor size (p=0.02), ER and EGFR (P = 0.01), PR and EGFR (P = 0.04), ER and PR (p< 0.001). No significant correlations were observed between age and histopathologic features (except tumor size), age and molecular markers, the molecular markers and histopathological features (except for PR), VEGF and standard molecular markers, EGFR and PR. Conclusion: Our study showed that majority of our breast cancer patients were younger age with large tumor size, lymph node positive and poorly differentiated tumors. Younger age women are more likely to present with larger tumor size as compared to older age groups. EGFR expression was most likely associated with ER and PR negative tumors. Assessment of multiple molecular markers aids to understand the biological behavior disease prognosis in Ethiopian population. It might also help to predict which group of patients might get more benefit from the selected treatment strategies and which are not.

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Keywords

Breast cancer, ER, PR, EGFR, VEGF-A, IHC, Histopathological features

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