Race modifies the association between breast carcinoma pathologic prognostic indicators and the positive status for HER‐2/neu

Abstract

BACKGROUNDInferences about the variations in the biology of breast carcinoma between African‐Americans and Caucasians have been reported. The difference in the prevalence of positive HER‐2/neu breast carcinoma was evaluated and the race‐specific risk was assessed for positive HER‐2/neu among a cohort of women diagnosed with their first primary breast carcinoma, given the accepted prognostic pathologic indicators for positive HER‐2/neu status.METHODSDemographic, clinical, and pathologic data were collected from existing databases. The status of HER‐2/neu was considered positive if the immunohistochemistry score was 3+ or if the fluorescent in situ hybridization indicated a ratio greater than 2. Multivariable logistic regression was used to determine the race‐specific risk for HER‐2/neu positive breast carcinoma.RESULTSThe difference in the prevalence of HER‐2/neu‐positive status between African‐American and Caucasian women was not statistically significant (P = 0.46). For Caucasian women the likelihood for positive HER‐2/neu was statistically significant and increased almost linearly within each stage with nuclear grade dedifferentiation relative to the reference group, women with Stage 1, Grade 1 carcinomas. For African‐American women, this risk was not significantly associated with stage, nuclear grade, their interaction term, or other pathologic prognostic indicators.CONCLUSIONSThe findings suggest that race modifies the association between the pathologic prognostic indicators of breast carcinoma and the likelihood of HER‐2/neu‐positive carcinoma. So far, clinical correlative studies of HER‐2/neu have not included race as an independent variable. Concerns about the limited generalizability and the need for validation of the findings across racial lines have been expressed previously. Cancer 2005. © 2005 American Cancer Society.

Prevalence and Prognostic Role of Triple-Negative Breast Cancer by Race: A Surveillance Study

“…Despite missing information, our finding of a lack of significant difference in HER2 positivity between black and white patients is corroborated by several earlier reports. 1,7,12,33,34,43 HER2 positivity in our study (IHC 2+ scores deemed either positive or negative) falls within the range of recent reports estimating prevalence to be 12% to 25% of sampled tumors, 12,43–46 which is a narrowing from initial estimates that ranged up to 40%. It is likely that early studies overestimated prevalence because these investigations tended to be composed of high-risk cohorts or proportionally more patients with regional or metastatic disease.…”

“…Our findings also are similar to previous reports that tumors from black patients with breast cancer tend to have significantly reduced ER or PR expression, 31,32 whereas HER2 status does not appear to vary by race. 7,33,34 Our findings suggest that divergent histologic distribution by race may underlie the disparity in TN status. Although the medullary subtype is relatively rare, we found that blacks had an almost 9-fold greater rate than that of white patients (3.3% vs. 0.40%), which is consistent with several earlier reports.…”

Population-based Estimate of the Prevalence of HER-2 Positive Breast Cancer Tumors for Early Stage Patients in the US

“…and Carey et al . found no significant difference in the prevalence of HER-2 tumors between African-American and white women (7, 12). However, Stark found grade and stage were associated with HER-2 status in whites but not in African-Americans (7).…”

HER2 in well differentiated breast cancer: is testing necessary?

“…Stark et al reported that whereas the risk of a positive HER2 status increased linearly with nuclear grade in Caucasian women, no correlation was seen among African American women [26]. HER2 expression may be dissociated from tumor grade in other patient groups as well.…”