How do estrogen and progesterone receptors (ER/PR) influence breast cancer?

Estrogen and progesterone receptors are critical components in understanding the biology of breast cancer. When estrogen and progesterone bind to their respective receptors on breast cells, these receptor-hormone complexes function as transcription factors that activate specific genes involved in cell proliferation and growth. This process contributes to the development and progression of breast cancer, particularly in hormone receptor-positive tumors, where the presence of these receptors indicates that the cancer cells require these hormones for growth.

The activation of genes by the receptor-hormone complex can lead to increased cell division and the potential for tumor growth. This is crucial for the proliferation of breast cancer cells, as the estrogen and progesterone signaling pathways stimulate cell cycle progression and inhibit apoptotic processes, enabling cancer cells to survive and multiply.

Understanding this mechanism emphasizes the importance of hormone receptor status in breast cancer treatment, as therapies targeting these receptors, such as estrogen blockers or aromatase inhibitors, have been developed to counteract the effects of these hormones and slow cancer progression.