Basal-Like Phenotype in a Breast Carcinoma Case Series from Sudan: Prevalence and Clinical/Pathological Correlations

Khalid Dafaallah Awadelkarim,Hussein M A Hamad,Nasr Eldin Elwali,Ida Biunno,Renato Mariani-Costantini,Ihsan Osman,Pasquale De Blasio,Elgizouli Omer Musa Elamin,Carmelo Arizzi,Massimo Costanzo Barberis,Salwa O Mekki

doi:10.4061/2011/806831

Abstract

Basal-like breast cancer, an aggressive subtype associated with high grade, poor prognosis, and younger age, is reported frequently in Africa. We analyzed the expression of the basal cytokeratins (CKs) 5/6 and 17 in a case series from Central Sudan and investigated correlations among basal CK status, ER, PgR, and Her-2/neu, and individual/clinicopathological data. Of 113 primary breast cancers 26 (23%), 38 (34%), and 46 (41%) were, respectively, positive for CK5/6, CK17, and combined basal CKs (CK5/6 and/or CK17). Combined basal CK+ status was associated with higher grade (P < .03) and inversely correlated with ER (P < .002), PgR (P = .004) and combined ER and/or PgR (P < .0002). Two clusters based on all tested markers were generated by hierarchical cluster analysis and k-mean clustering: I: designated “hormone receptors positive/luminal-like” and II: designated “hormone receptors negative”, including both basal-like and Her-2/neu+ tumors. The most important factors for dataset variance were ER status, followed by PgR, CK17, and CK5/6 statuses. Overall basal CKs were expressed in a fraction of cases comparable to that reported for East and West African case series. Lack of associations with age and tumor size may represent a special feature of basal-like breast cancer in Sudan.

Highlights

Cytokeratins (CKs) are used as differentiation markers in breast cancer (BC), since their expression is thought to remain stable in carcinogenesis [1]
In a previous study we found that a BC case series from Khartoum, Central Sudan, was comparable to one from Milan, Northern Italy, in combined hormone receptors status and BC subtypes [37]
Recent studies found that the basal-like phenotype was frequent in West (Nigeria and Senegal) and East (Uganda) African BC case series, where it was associated with features of poor prognosis [33,34,35,36]

Summary

Introduction

Cytokeratins (CKs) are used as differentiation markers in breast cancer (BC), since their expression is thought to remain stable in carcinogenesis [1]. BC may be luminal or basal with regard to CK phenotype, with some tumors coexpressing both basal and luminal CKs [2]. This is supported by microarray expression profiling that. Pathology Research International classifies BC into five prognostically and clinically relevant molecular subtypes, luminal A, luminal B, basal-like, Her2/neu, and normal breast-like [5,6,7,8,9,10,11,12,13,14,15,16]. Most basal-like BCs do not express ER, PgR, or Her-2/neu, in case series of different origin 14% to 45% of the cases were reported to express at least one of these markers [7, 9, 14]

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Discussion

Conclusion