The Aggressiveness of African breast cancer: An expose’ on CD44+CD24-/low breast cancer stem cell

Abstract Breast cancer (BC) in Africans and people of African descent is generally aggressive, with poorer prognosis and worse clinical outcomes. The molecular basis of this is however not entirely understood. The CD44+ / CD24-/low BC stem cell is known for its tumourigenic potential, tumour aggressiveness and its association with poor prognosis. This study identifies the relationship between CD44+/ CD24-/low BC stem cells and clinicopathological features of breast cancer in an African population.Methodology A Ghanaian BC cohort (n= 222) was used to assess CD44 and CD24 expression. Tissue microarray was constructed from the cohort samples and Immunohistochemically stained with CD44 and CD24 antibodies. The associations between clinicopathological features and the expression of the individual markers and their combinations were analysed. Results Of the total 222 breast cancer samples, 81.9 % were cytoplasmic CD24 positive and were associated with higher tumour grade (OR-3.623; r=0.199; p=0.004), gender (OR-9.514; p=0.028), clinical prognostic grading (OR-2.357 r= 0.162; p=0.027) and Her2 positivity (OR-0.216; r=-0.155; p=0.026). CD44 was associated with higher tumour grade (OR-3.148; r= 0.145; p-0.037), and increased mitotic count (OR-3.043, r= 0.173; p=0.028). There was no association between CD44 expression and hormone receptor status. Together, CD44+/CD24-/low staining was associated with higher tumour grade (OR-3.162; r=0.166; p=0.018), gender (OR- 12.0; p=0.012), and higher clinical prognostic staging (OR- 2.888; r=0.186; p=0.011). An inverse association of CD44+CD24+ was found with tumour grade (OR-0.220; r=-0.246; p=0.000), mitotic count (OR-0.406; r=-0.190; p=0.017) and clinical prognostic staging (OR-0.486; r=-0.151; p=0.040). There was no association between CD44-CD24+ and all the clinicopathological features.Conclusion Combined, CD44+CD24-/low was associated with poor prognosis and tumour aggression and may contribute to the tumour aggressiveness of African breast cancer. CD24 expression as a stand-alone marker was found to correlate with clinical and pathological indicators of tumour aggressiveness and poor prognosis.