THE RELATIONSHIP BETWEEN MENSTRUAL FACTORS AND BREAST CANCER ACCORDING TO ESTROGEN RECEPTOR STATUS OF TUMOR: A CASE-CONTROL STUDY IN AFRICAN-AMERICAN WOMEN

Background: Exposure to estrogen is a risk fac-tor for breast cancer. Since estrogen executes its effect through estrogen receptors (ERs), the relationship between menstrual factors, which are estrogen-related, and breast cancer may be different depending upon ER status of tumors. This case-control study aimed to examine such a relationship according to ER status of breast cancer in African-American women. Methods: Cases were 304 African-American patients pathologically diagnosed with breast cancer during 1995–1998, who were 20–64 years old and lived in 3 Tennessee counties. Controls were 305 African-American women without breast cancer, selected through ran