Figure 4From: Estrogen receptor-α and progesterone receptor are expressed in label-retaining mammary epithelial cells that divide asymmetrically and retain their template DNA strandsPeriductal stromal cells retain nuclear label. The nuclear label [3H]thymidine is detected in mammary tissue that has been processed for (a) ER-α or (b) PR following a 7-week chase period. Black arrows indicate periductal stromal cells that are [3H]thymidine positive. Scale bars = 5 μm. ER, estrogen receptor; PR, progesterone receptor.Back to article page