Race and breast cancer survival by intrinsic subtype based on PAM50 gene expression

Candyce H. Kroenke, Carol Sweeney, Marilyn L. Kwan, Charles P. Quesenberry, Erin K. Weltzien, Laurel A. Habel, Adrienne Castillo, Phillip S. Bernard, Rachel E. Factor, Lawrence H. Kushi, Bette J. Caan

Research output: Contribution to journalArticle

17 Scopus citations

Abstract

To evaluate whether differences in PAM50 breast cancer (BC) intrinsic (Luminal A, Luminal B, Basal-like, and HER2-enriched) subtypes help explain the Black-White BC survival disparity. Utilizing a stratified case-cohort design, this study included 1,635 women from the Pathways and Life After Cancer Epidemiology cohorts, selecting women with tumors based upon IHC classification, recurrences, and deaths.One millimeter punches were obtained from tumor tissue, and expression of the PAM50 genes for molecular subtype was determined by RT-qPCR of extracted RNA. Cox proportional hazards models were used to analyze associations between race and BC outcomes, adjusted for PAM50 BC subtype. All tests of statistical significance were two-sided. Black women had a higher prevalence of the Basal-like BC subtype. Adjusted for potential confounding variables and disease characteristics at diagnosis, Black women had higher risks of recurrence (HR 1.65, 95% CI 1.06-2.57) and breast cancer-specific mortality (HR 1.71, 95% CI 1.02-2.86) than White women, but adjusting further for subtype did not attenuate survival disparities. By contrast, Hispanic women had a lower risk of recurrence (HR 0.54, 95% CI 0.30-0.96) than Whites. Among those with the Basal-like subtype, Black women had a similar recurrence risk as women in other race groups but a higher recurrence risk for all other subtypes. Hispanic women had a lower recurrence risk within each subtype, though associations were not significant, given limited power. Although Black women had a higher risk of the Basal-like subtype, which has poor prognosis, this did not explain the Black-White BC survival disparity.

Original languageEnglish (US)
Pages (from-to)689-699
Number of pages11
JournalBreast Cancer Research and Treatment
Volume144
Issue number3
DOIs
StatePublished - 2014
Externally publishedYes

Keywords

  • Breast cancer mortality
  • Breast cancer survival
  • Ethnicity
  • Gene expression
  • Intrinsic subtype
  • Molecular subtype
  • PAM50
  • Race

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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  • Cite this

    Kroenke, C. H., Sweeney, C., Kwan, M. L., Quesenberry, C. P., Weltzien, E. K., Habel, L. A., Castillo, A., Bernard, P. S., Factor, R. E., Kushi, L. H., & Caan, B. J. (2014). Race and breast cancer survival by intrinsic subtype based on PAM50 gene expression. Breast Cancer Research and Treatment, 144(3), 689-699. https://doi.org/10.1007/s10549-014-2899-5