Human Mammary Epithelial Cells (HMECs) are cells that originate from the mammary gland or breast tissue. They are an essential component of the ducts and lobules in the breast, where milk is produced and transported.

HMECs have been extensively used in biological and medical research as a model system to understand the biology of the mammary gland under normal and diseased conditions, including breast cancer. HMECs can be sourced from breast tissue obtained through reduction mammoplasties or other surgeries, and even from human milk.

These cells can be cultured in laboratories under specific conditions that support their growth and survival. However, primary HMECs, which are directly isolated from tissue, have a limited lifespan in culture due to a process called cellular senescence.

To overcome this limitation, scientists have developed methods to “immortalize” HMECs, extending their lifespan so they can be grown indefinitely in the lab. This process usually involves altering specific genes that control cell division and senescence.

While this makes the cells more useful for long-term studies, it’s important to remember that these modifications can also influence the cells’ behavior and may make them less representative of normal mammary epithelial cells in the body.

HMECs are used to study many aspects of mammary gland biology, including how cells respond to hormones, how they interact with other cells in the tissue, and what changes occur when they become cancerous. They’re also used in drug testing and development, providing an in vitro model to study the effects of potential therapeutic compounds.