ABSTRACT: Functionally active estrogen receptor isoform profiles in the breast tumors of African American women are different from the profiles in breast tumors of Caucasian women BACKGROUND: Several cancer surveys have shown that African-American women (AAW) develop highly aggressive breast tumors and experience about three times higher mortality rates compared with other populations. Generally, breast tumors in AAW are poorly differentiated or undifferentiated and exhibit increased frequency of nuclear atypia, higher mitotic activity, higher S-phase fraction, and tumor necrosis. The molecular factors responsible for these tumor characteristics are mostly unknown. CONCLUSIONS: The data presented here show for the first time that functionally active ER isoform profiles in the breast tumors of AAW are different from those in Caucasian women. The tumors in AAW are characterized by decreased levels of the protective ER isoform and elevated levels of the constitutively active ER exon 5 isoform. Variations in estrogen-mediated signaling because of the alterations in these two ER isoforms may account in part for differences in tumor biology between AAW and Caucasian women. [02/04/2002; Cancer Online (Free Registration Required)] AACR Abstract #LB-130, 2003 Era of Hope, 2005 Abstract Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.