Mortality risk of black women and white women with invasive breast cancer by hormone receptors, HER2, and p53 status

Abstract

BackgroundBlack women are more likely than white women to have an aggressive subtype of breast cancer that is associated with higher mortality and this may contribute to the observed black-white difference in mortality. However, few studies have investigated the black-white disparity in mortality risk stratified by breast cancer subtype, defined by estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) status. Furthermore, it is not known whether additional consideration of p53 protein status influences black-white differences in mortality risk observed when considering subtypes defined by ER, PR and HER2 status.MethodsFour biomarkers were assessed by immunohistochemistry in paraffin-embedded breast tumor tissue from 1,204 (523 black, 681 white) women with invasive breast cancer, aged 35–64 years at diagnosis, who accrued a median of 10 years’ follow-up. Multivariable Cox proportional hazards regression models were fit to assess subtype-specific black-white differences in mortality risk.ResultsNo black-white differences in mortality risk were observed for women with triple negative (ER-negative [ER-], PR-, and HER2-) subtype. However, older (50–64 years) black women had greater overall mortality risk than older white women if they had been diagnosed with luminal A (ER-positive [ER+] or PR+ plus HER2-) breast cancer (all-cause hazard ratio, HR, 1.88; 95% confidence interval, CI, 1.18 to 2.99; breast cancer-specific HR, 1.51; 95% CI, 0.83 to 2.74). This black-white difference among older women was further confined to those with luminal A/p53- tumors (all-cause HR, 2.22; 95% CI, 1.30 to 3.79; breast cancer-specific HR, 1.89; 95% CI, 0.93 to 3.86). Tests for homogeneity of race-specific HRs comparing luminal A to triple negative subtype and luminal A/p53- to luminal A/p53+ subtype did not achieve statistical significance, although statistical power was limited.ConclusionsOur findings suggest that the subtype-specific black-white difference in mortality risk occurs mainly among older women diagnosed with luminal A/p53- breast cancer, which is most likely treatable. These results further suggest that factors other than subtype may be relatively more important in explaining the increased mortality risk seen in older black women.

Racial/ethnic differences in breast cancer survival by inflammatory status and hormonal receptor status: an analysis of the Surveillance, Epidemiology, and End Results data

“…Our study found similar racial/ethnic differences regardless of tumor characteristics (hormone receptor status and inflammatory histology). This is consistent with some previous studies, which also suggested similar racial/ethnic difference for breast cancer with various pathologic features (23, 24). These research results imply that factors other than these tumor features may play a large role in racial/ethnic disparities in breast cancer survival.…”

Copy Number Analysis of the <b><i>DLX4</i></b> and <b><i>ERBB2 </i></b>Genes in South African Breast Cancer Patients

“…In Sub-Saharan African patients a 20% frequency of ERBB2 protein expression was reported in the few published studies [Adebamowo et al, 2008;Yarney et al, 2008;Ly et al, 2012]. In a study conducted in South African patients, van Bogaert et al [2013] observed a frequency of 26% of ERBB2 overexpression, which is similar to the one observed in our cases (30.3% ERBB2 overexpression/29.7% ERBB2 copy number gain) and in line with the rates of ERBB2 protein expression reported in most of the African-American patient studies [Fregene and Newman, 2005;Adebamowo et al, 2008, Ma et al, 2013.…”

“…The general frequency of ERBB2 gains in our cases was in concordance with ERBB2 protein overexpression as evaluated by IHC. Several studies have analyzed the distribution of ERBB2 protein expression among different races, reporting contrasting findings [Joslyn, 2002;Carey et al, 2006;Adebamowo et al, 2008;Telli et al, 2011;Clarke et al, 2012;Ma et al, 2013;Adjei et al, 2014]. In Sub-Saharan African patients a 20% frequency of ERBB2 protein expression was reported in the few published studies [Adebamowo et al, 2008;Yarney et al, 2008;Ly et al, 2012].…”

Breast Cancer Mortality in African-American and Non-Hispanic White Women by Molecular Subtype and Stage at Diagnosis: A Population-Based Study

“…In particular, African-American women are more likely than white women to be diagnosed with triple-negative breast cancer, which, because of its lack of expression for the three molecular markers, does not currently have targeted treatment options (7, 15-17). A few studies have measured the contribution of molecular subtype to racial/ethnic disparities in breast cancer survival (18-20), but the findings were inconsistent when comparing survival in African-American patients with whites. One study found mortality risk difference between African-American and white women occurs only among older women diagnosed with luminal A/p53- but not with triple-negative breast cancer (18), whereas another two studies suggested higher overall mortality (19) and breast cancer specific mortality (20) in African-American than white patients with the triple-negative subtype.…”