Insulin resistance contributes to racial disparities in breast cancer prognosis in US women.
Breast Cancer Res
; 22(1): 40, 2020 05 12.
Article
em En
| MEDLINE
| ID: mdl-32393319
ABSTRACT
BACKGROUND:
Racial disparities in breast cancer survival between Black and White women persist across all stages of breast cancer. The metabolic syndrome (MetS) of insulin resistance disproportionately affects more Black than White women. It has not been discerned if insulin resistance mediates the link between race and poor prognosis in breast cancer. We aimed to determine whether insulin resistance mediates in part the association between race and breast cancer prognosis, and if insulin receptor (IR) and insulin-like growth factor receptor (IGF-1R) expression differs between tumors from Black and White women.METHODS:
We conducted a cross-sectional, multi-center study across ten hospitals. Self-identified Black women and White women with newly diagnosed invasive breast cancer were recruited. The primary outcome was to determine if insulin resistance, which was calculated using the homeostatic model assessment of insulin resistance (HOMA-IR), mediated the effect of race on prognosis using the multivariate linear mediation model. Demographic data, anthropometric measurements, and fasting blood were collected. Poor prognosis was defined as a Nottingham Prognostic Index (NPI) > 4.4. Breast cancer pathology specimens were evaluated for IR and IGF-1R expression by immunohistochemistry (IHC).RESULTS:
Five hundred fifteen women were recruited (83% White, 17% Black). The MetS was more prevalent in Black women than in White women (40% vs 20%, p < 0.0001). HOMA-IR was higher in Black women than in White women (1.9 ± 1.2 vs 1.3 ± 1.4, p = 0.0005). Poor breast cancer prognosis was more prevalent in Black women than in White women (28% vs 15%. p = 0.004). HOMA-IR was positively associated with NPI score (r = 0.1, p = 0.02). The mediation model, adjusted for age, revealed that HOMA-IR significantly mediated the association between Black race and poor prognosis (ß = 0.04, 95% CI 0.005-0.009, p = 0.002). IR expression was higher in tumors from Black women than in those from White women (79% vs 52%, p = 0.004), and greater IR/IGF-1R ratio was also associated with higher NPI score (IR/IGF-1R > 1 4.2 ± 0.8 vs IR/IGF-1R = 1 3.9 ± 0.8 vs IR/IGF-1R < 1 3.5 ± 1.0, p < 0.0001).CONCLUSIONS:
In this multi-center, cross-sectional study of US women with newly diagnosed invasive breast cancer, insulin resistance is one factor mediating part of the association between race and poor prognosis in breast cancer.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Negro ou Afro-Americano
/
Neoplasias da Mama
/
Resistência à Insulina
/
População Branca
/
Disparidades em Assistência à Saúde
Tipo de estudo:
Clinical_trials
/
Observational_studies
/
Prevalence_studies
/
Prognostic_studies
/
Risk_factors_studies
Limite:
Female
/
Humans
/
Middle aged
País/Região como assunto:
America do norte
Idioma:
En
Revista:
Breast Cancer Res
Assunto da revista:
NEOPLASIAS
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
Estados Unidos