Histological Features and Tissue Microarray Taxonomy of Nigerian Breast Cancer Reveal Predominance of the High-Grade Triple-Negative Phenotype

Abstract

Introduction: Little is known about the biology, molecular profile and hence optimal treatment of African Nigerian breast cancer. The aim of this work, therefore, was to characterize the histology and molecular profile of Nigerian breast cancer. Methods: Breast carcinomas from women at 6 centres of similar tribal origin in Nigeria were reviewed and assembled into tissue microarrays (TMAs), and sections were stained for hormone receptors, i.e. estrogen receptor (ER)α, ERβ1, ERβ progesterone receptor (PR) and androgen receptor, cyclin D, HER2, Ki67 and cytokeratins (CKs), i.e. CK5/6 and CK14 (basal) and CK18 and 19 (luminal). Results: A total of 835 tumours were analysed. The mean age at diagnosis was 48.62 ± 12.41 years. The most common histological subtype was ductal NST (no-special-type) carcinoma (87.3%). Over 90% of the tumours were grade 2 or 3. The predominant molecular phenotype was the non-basal, triple-negative type (47.65%) followed by the HER2-positive group (19.6%). The percentage of ER-, PR- and HER2-positive tumours was 22.4, 18.9 and 18.8%, respectively. Conclusion: Nigerian breast cancer predominantly has a high-grade, triple-negative profile. It occurs at a younger age and bears similarities at the molecular level to pre-menopausal breast cancer in white women, with remarkably lower levels of ERβ expression. The early presentation and histological and molecular phenotype may explain the poor prognosis, and tailoring treatment strategies to target this unique profile are required.

Breast Cancer in a Lagos Facility: Implications for the Institution of a Cancer Screening Programme

“…This result is similar to the report from the cancer registries in Ibadan and Abuja, where 42.5 and 57.1%, respectively, occurred in patients younger than 45 years [1]. In another large study of 835 cases from 6 large centres in south-west Nigeria, 60% occurred in patients younger than 40 years, and 85.5% of the cases occurred in patients younger than 50 years [4]. Studies from other African countries corroborate these findings with mean/median ages ranging from 46 to 52.3 years [9][10][11][12][13][14][15][16][17].…”

“…Basal-type cancers are seen in only 15% of this population [6]. On the other hand, triple-negative cancers are seen with greater frequency among blacks, accounting for as high as 60.5% of all breast cancer cases in some African studies [4,[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33]. In our study, most cancers (41.9%) were of high nuclear grade, triple negative (42.1%), and unassociated with DCIS (52.3%).…”

“…Triplenegative breast cancers are therefore more genetically linked to blacks both in western societies and in Africa. It is pertinent to note, however, that though the basal type is the commonest of triple-negative breast cancers among black women in western societies, Titloye et al [4] reported a predominance of non-basal type triple-negative cancer in SW Nigeria. More studies are needed to corroborate this finding.…”

“…Breast cancer in blacks has well-documented epidemiological and biological differences from cases reported in the western literature. These include the earlier age of occurrence, the late stage of presentation, a predominance of the triple-negative immunophenotype, and a more aggressive biology [4,5]. These differences have great implications for the adoption of a breast cancer screening programme.…”

Differential Expression of MicroRNAs in Breast Cancers from Four Different Ethnicities

“…We have previously shown, using tissue microarrays, that breast cancer in Nigerian patients is enriched for the TN phenotype [20]. There is limited, predominantly epidemiological, data on ethnic breast cancer within the UK population that points to similar variation in the biology and outcome of the disease across different backgrounds [21, 22].…”