Mammary gland stem cells: current status and future challenges

Area of Science:

• Cell Biology
• Developmental Biology
• Cancer Research

Background:

• The cellular origins of epithelial cells in mammary gland development, homeostasis, and cancer remain poorly understood.
• Distinct cell subsets, including stem cell-like populations, are proposed in human breast epithelium and carcinomas.
• The mouse model is crucial for studying mammary gland development and human breast epithelium xenotransplantation.

Purpose of the Study:

• To review and discuss similarities and differences between mouse and human mammary gland development.
• To emphasize the identity and localization of mammary stem cells in both species.
• To explore the influence of the microenvironment on mammary gland development and stem cell biology.

Main Methods:

• Review of existing literature on mouse and human mammary gland development.
• Comparative analysis of stem cell properties and microenvironmental influences.
• Discussion of technical advancements in interrogating cell populations and individual cells.

Main Results:

• Recent advances have significantly improved understanding of normal mammary gland development and maintenance.
• Similarities and differences between mouse and human mammary gland development are highlighted.
• The role of the microenvironment in mammary gland development and stem cell function is discussed.

Conclusions:

• While mouse models provide valuable insights, significant discrepancies exist between mouse and human mammary glands.
• These discrepancies, particularly concerning mammary stem cells and their microenvironment, must be considered in future research.
• Current and future models of mammary stem cell biology should account for species-specific differences.