High triple-negative breast cancer prevalence and aggressive prognostic factors in Barbadian women with breast cancer.

BACKGROUND: Women of African ancestry (WAA) are disproportionately affected by triple-negative breast cancer (TNBC), which remains one of the most clinically challenging breast cancer (BCa) subtypes. This study investigated the prevalence of TNBC and epidemiological trends for BCa in Barbados, a Caribbean island with a high percentage of African ancestry. METHODS: Pathology reports for all BCa cases between 2007 and 2016 were collected from the sole hospital in Barbados and reviewed. The clinicopathological data collected included age, tumor grade, lymph node status, and hormone receptor status as determined by immunohistochemistry. BCa data for non-Hispanic white (NHW) and non-Hispanic black (NHB) American populations were accessed from the Surveillance, Epidemiology, and End Results database. RESULTS: There were 1997 BCa cases in Barbados between 2007 and 2016 for an estimated incidence rate of 135.1 per 100,000 women in Barbados (standardized to the US population, where the standardized incidence rates for NHBs and NHWs were 141.4 and 152.6 per 100,000, respectively). Age-specific incidence rates in Barbados for this period were consistently higher in younger age groups (15-59 years) in comparison with NHWs and NHBs. Between 2010 and 2016 in Barbados, a TNBC prevalence of 25% was observed, whereas TNBC prevalences of 21% and 10% were observed in NHBs and NHWs, respectively. CONCLUSIONS: The BCa incidence was higher in younger Barbadian women than NHWs and NHBs, and the TNBC prevalence was ~2.5 times higher than the prevalence in NHWs. This hints at a possible genetic predisposition and other socioeconomic factors that could explain the high TNBC prevalence and aggressive clinical course in WAA globally.

Kaiso is highly expressed in TNBC tissues of women of African ancestry compared to Caucasian women.

PURPOSE: Triple-negative breast cancer (TNBC) is most prevalent in young women of African ancestry (WAA) compared to women of other ethnicities. Recent studies found a correlation between high expression of the transcription factor Kaiso, TNBC aggressiveness, and ethnicity. However, little is known about Kaiso expression and localization patterns in TNBC tissues of WAA. Herein, we analyze Kaiso expression patterns in TNBC tissues of African (Nigerian), Caribbean (Barbados), African American (AA), and Caucasian American (CA) women. METHODS: Formalin-fixed and paraffin embedded (FFPE) TNBC tissue blocks from Nigeria and Barbados were utilized to construct a Nigerian/Barbadian tissue microarray (NB-TMA). This NB-TMA and a commercially available TMA comprising AA and CA TNBC tissues (AA-CA-YTMA) were subjected to immunohistochemistry to assess Kaiso expression and subcellular localization patterns, and correlate Kaiso expression with TNBC clinical features. RESULTS: Nigerian and Barbadian women in our study were diagnosed with TNBC at a younger age than AA and CA women. Nuclear and cytoplasmic Kaiso expression was observed in all tissues analyzed. Analysis of Kaiso expression in the NB-TMA and AA-CA-YTMA revealed that nuclear Kaiso H scores were significantly higher in Nigerian, Barbadian, and AA women compared with CA women. However, there was no statistically significant difference in nuclear Kaiso expression between Nigerian versus Barbadian women, or Barbadian versus AA women. CONCLUSIONS: High levels of nuclear Kaiso expression were detected in patients with a higher degree of African heritage compared to their Caucasian counterparts, suggesting a role for Kaiso in TNBC racial disparity.