Literature review of data-based models for identification of factors associated with racial disparities in breast cancer mortality

Historical redlining and clustering of present-day breast cancer factors

PURPOSE

Historical redlining, a 1930s-era form of residential segregation and proxy of structural racism, has been associated with breast cancer risk, stage, and survival, but research is lacking on how known present-day breast cancer risk factors are related to historical redlining. We aimed to describe the clustering of present-day neighborhood-level breast cancer risk factors with historical redlining and evaluate geographic patterning across the US.

METHODS

This ecologic study included US neighborhoods (census tracts) with Home Owners' Loan Corporation (HOLC) grades, defined as having a score in the Historic Redlining Score dataset; 2019 Population Level Analysis and Community EStimates (PLACES) data; and 2014-2016 Environmental Justice Index (EJI) data. Neighborhoods were defined as redlined if score ≥ 2.5. Prevalence quintiles of established adverse and protective breast cancer factors relating to behavior, environment, and socioeconomic status (SES) were used to classify neighborhoods as high-risk or not. Factor analysis grouped factors into domains. Overall and domain-specific scores were calculated for each neighborhood according to historical redlining status. Percent difference in score by historical redlining was used to assess differences in average scores, with Wilcoxon-Mann-Whitney test used to estimate significance. Kappa statistic was used to estimate concordance between historical redlining status and high-risk status. Heatmaps of scores were created to compare spatial clustering of high-risk factors to historical redlining.

RESULTS

We identified two domains: (1) behavior + SES; (2) healthcare. Across the US, redlined neighborhoods had significantly more breast cancer factors than non-redlined (redlined neighborhoods = 5.41 average high-risk factors vs. non-redlined = 3.55 average high-risk factors; p < 0.0001). Domain-specific results were similar (percent difference for redlined vs. non-redlined: 39.1% higher for behavior + SES scale; 23.1% higher for healthcare scale). High-scoring neighborhoods tended to spatially overlap with D-grades, with heterogeneity by scale and region.

CONCLUSION

Breast cancer risk factors clustered together more in historically redlined neighborhoods compared to non-redlined neighborhoods. Our findings suggest there are regional differences for which breast cancer factors cluster by historical redlining, therefore interventions aimed at redlining-based cancer disparities need to be tailored to the community.

West African Genetic Ancestry and Breast Cancer Outcomes Among Black Women

Importance

Young Black women bear a disproportionate burden of breast cancer deaths compared with White women, yet they remain underrepresented in genomic studies.

Objective

To evaluate the association of biological factors, including West African genetic ancestry, and nonbiological factors with disease-free survival (DFS) among young Black women with breast cancer.

Design, Setting, and Participants

This observational cohort study included Black women diagnosed with invasive breast cancer between January 1, 2005, and December 31, 2016. Participants diagnosed with breast cancer at age 50 years or younger were recruited through the Florida and Tennessee state cancer registries. The final analysis was completed between June and September 2024.

Exposure

West African genetic ancestry.

Main Outcomes and Measures

A multivariable model was developed to evaluate the association between West African genetic ancestry and breast cancer DFS, adjusting for immunohistochemistry subtype, lymph node (LN) status, and full-time employment.

Results

This study included 687 Black women with early-stage invasive breast cancer. Their median age at diagnosis was 44 years (IQR, 38-47 years), and the median follow-up was 10 years (IQR, 7-11 years). In multivariable analysis, triple-negative breast cancer (TNBC) and LN involvement were associated with shorter breast cancer DFS (hazard ratio, 1.81 [95% CI, 1.20-2.73] and 1.77 [95% CI, 1.30-2.41], respectively), whereas full-time employment was associated with improved outcomes (hazard ratio, 0.44 [95% CI, 0.30-0.63]). Among the 551 participants for whom global genetic ancestry could be assessed, having a higher percentage of West African genetic ancestry was associated with shorter breast cancer DFS among 246 participants in the hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (ERBB2 [formerly HER2])-negative subgroup (hazard ratio, 1.45 [95% CI, 1.04-2.04]). Of the 369 participants (53.7%) with PAM50 data available, basal (133 [36.0%]) and luminal B (107 [29.0%]) subtypes were the most common. Among the 179 patients with HR-positive/ERBB2-negative disease and PAM50 data available, luminal B and basal subtypes combined were also overrepresented (81 [45.3%] and 24 [13.4%], respectively) compared with luminal A (70 [39.1%]).

Conclusions and Relevance

In this study of young Black women with breast cancer, having a higher percentage of West African genetic ancestry, TNBC, and LN involvement were associated with shorter breast cancer DFS. Interestingly, full-time employment was associated with improved breast cancer DFS. These findings highlight the importance of considering genetic ancestry beyond self-reported race and accounting for social determinants of health, in efforts to improve survival outcomes among Black women with breast cancer.

Atractylenolide-1 affects glycolysis/gluconeogenesis by downregulating the expression of TPI1 and GPI to inhibit the proliferation and invasion of human triple-negative breast cancer cells

Atractylenolide-1 (AT-1) is a major octanol alkaloid isolated from Atractylodes Rhizoma and is widely used to treat various diseases. However, few reports have addressed the anticancer potential of AT-1, and the underlying molecular mechanisms of its anticancer effects are unclear. This study aimed to assess the effect of AT-1 on triple-negative breast cancer (TNBC) cell proliferation and migration and explore its potential molecular mechanisms. Cell invasion assays confirmed that the number of migrating cells decreased after AT-1 treatment. Colony formation assays showed that AT-1 treatment impaired the ability of MDA-MB-231 cells to form colonies. AT-1 inhibited the expression of p-p38, p-ERK, and p-AKT in MDA-MB-231 cells, significantly downregulated the proliferation of anti-apoptosis-related proteins CDK1, CCND1, and Bcl2, and up-regulated pro-apoptotic proteins Bak, caspase 3, and caspase 9. The gas chromatography-mass spectroscopy results showed that AT-1 downregulated the metabolism-related genes TPI1 and GPI through the glycolysis/gluconeogenesis pathway and inhibited tumor growth in vivo. AT-1 affected glycolysis/gluconeogenesis by downregulating the expression of TPI1 and GPI, inhibiting the proliferation, migration, and invasion of (TNBC) MDA-MB-231 cells and suppressing tumor growth in vivo.

Racial disparities in survival outcomes among breast cancer patients by molecular subtypes

PURPOSE

Differences in tumor biology, genomic architecture, and health care delivery patterns contribute to the breast cancer mortality gap between White and Black patients in the US. Although this gap has been well documented in previous literature, it remains uncertain how large the actual effect size of race is for different survival outcomes and the four breast cancer subtypes.

METHODS

We established a breast cancer patient cohort at the University of Chicago Comprehensive Cancer Center. We chose five major survival outcomes to study: overall survival, recurrence-free survival, breast-cancer-specific survival, time-to-recurrence and post-recurrence survival. Cox proportional hazards models were used to estimate the hazard ratios between Black and White patients, adjusting for selected patient, tumor, and treatment characteristics, and also stratified by the four breast cancer subtypes.

RESULTS

The study included 2795 stage I-III breast cancer patients (54% White and 38% Black). After adjusting for selected patient, tumor and treatment characteristics, Black patients still did worse than White patients in all five survival outcomes. The racial difference was highest within the HR-/HER2+ subgroup, in both overall survival (hazard ratio = 4.00, 95% CI 1.47-10.86) and recurrence-free survival (hazard ratio = 3.00, 95% CI 1.36-6.60), adjusting for age at diagnosis, cancer stage, and comorbidities. There was also a significant racial disparity within the HR+/HER2- group in both overall survival and recurrence-free survival.

CONCLUSIONS

Our study confirmed that racial disparity existed between White and Black breast cancer patients in terms of both survival and recurrence, and found that this disparity was largest among HR-/HER2+ and HR+/HER2- patients.