Adipose Tissue and Desmoplastic Response in Breast Cancer

Breast tumors belong to a group of neoplastic lesions which, under the influence of tumoral cell products, originate a fibrous structure responsible for the dense and hard consistency of the tumoral mass. This trait also constitutes a factor that increases the relative risk of tumor recurrence (Hasabe et al., 1998). Myofibroblasts have been identified as major players in this phenomenon, acting either as producers of extracellular matrix (ECM) proteins and/or as functioning as elastic components of the tumor structure (Hinz B., 2007). Taken together, these pro-fibrotic processes are known as “tumoral desmoplastic reactions” (Shao et al., 2000). The origin of the fibroblastic component in tumors is controversial. On one hand, it has been proposed that fibroblasts derive essentially from epithelia under an epithelial-tomesenchymal transition (EMT) or, on the other, that the abundance of fibroblasts-like cells come from a dedifferentiation process by which mature adipose cells revert to fibroblastic not lipid ladencells (Taylor et al., 2010, Guerrero et al, 2010). In any case, the fibrotic outcome seems to be the result of a fluid cross-talk of signals among the predominant adipose stroma and epithelia. Epithelial control of mammary adipose cells is also observed under physiological conditions. During pregnancy and lactation, reproductive hormones induce the expansion and terminal differentiation of the mammary epithelium into secretory, milk-producing, lobular alveoli in a process that also includes the dedifferentiation of adipocytes into tiny preadipocytes (Wiseman and Werb, 2002). To further analyze the current hypothesis on the origin and possible fate or breast adipose tissue in the context of a tumoral breast, some aspects of breast adipose tissue need to be discussed in more detail.