**Postlactational Involution: Molecular Mechanisms and Relevance for Breast Cancer Development**

Edith C. Kordon and Omar A. Coso

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/66526

#### **Abstract**

Mammary gland tissue changes appearance and functionality in different sequential steps. The tissue of virgin, pregnant, or lactating mammary glands changes controlled by finely regulated physiological processes. A fourth stage (involution), triggered upon weaning, involves remodeling, and the gland regresses to resemble a prepregnant stage. This highly complex process characterized by a high degree of epithelial cell death and tissue remodeling can be divided into phases, which can be independent of each other. The present article describes a variety of signaling pathway components, transcription factors, and mRNA stabilization proteins that play a role in the regulation of cell fate during the involution process. These molecular actors are finely related in health to trigger the delicate mechanism that govern involution after weaning, leaving the gland in a latent stage until needed again. Importantly, it has been shown that this process may contribute to cancer development in the years following childbirth, mainly because of the involvement of inflammatory and remodeling factors.

**Keywords:** mammary gland involution, transcription factors, inflammatory cytokines, STATs, cell death, TNF-α, mRNA stability, breast cancer
