Yes, there is a well-established link between endogenous sex hormones, such as estrogen and progesterone, and breast cancer. High levels of these hormones in the blood have been associated with an increased risk of breast cancer in postmenopausal women. This is because estrogen and progesterone can stimulate the growth of breast cells, including cancer cells. Understanding your hormone levels and their impact on your breast cancer risk is an essential part of the personalized care we offer at the Texas Breast Center.