%0 Journal Article
%T Tumour-stromal interactions: Role of the stroma in mammary development
%A Gary B Silberstein
%J Breast Cancer Research
%D 2001
%I BioMed Central
%R 10.1186/bcr299
%X Mammary gland development occurs in two morphogenetically distinct phases. The first begins with the differentiation of a mammary ductal rudiment from the embryonic epidermis and ends after puberty with an elegant arborated system of ducts (Fig. 1a). In the second phase, beginning with pregnancy, acinar milk-secretory lobules develop on this primary framework. This review focuses on organotypic branching morphogenesis as it occurs during the ductal, as opposed to the lobular, phase, because it is during ductal development that stromal influences are demonstrably the most crucial to organogenesis. In addition, more than 90% of human mammary carcinomas are ductal in origin and it is becoming increasingly clear that the subversion of reciprocal signals between parenchyma and stroma are an important aspect of tumor progression. Finally, although reference will be made to the influence of the embryonic stroma, called the mesenchyme, on mammary development, the emphasis will be on postnatal events because these arguably have a more direct bearing on breast cancer.By parturition, the mammary stroma comprises multiple cellular and acellular elements. In the mouse, which is the most thoroughly studied model and the focus of this review, adipocytes are the most abundant cell type, followed by fibroblasts, various migratory blood cells, endothelial cells (blood vessels), and nerve cells. Acellular elements include fibrous and non-fibrous collagens, proteoglycans, and glycoproteins, all of which provide mechanical support to the tissue as well as forming a dynamic, developmentally active extracellular matrix/basal lamina complex at the epithelial-stromal boundary (Fig. 1b) [1]. This complex connective tissue is found in the mammary glands of different species with various ratios of fibrous to fatty elements [2], and it is within this matrix that mammary ducts elongate, arborate, and, finally, terminate growth (Fig. 1a).The mammary gland pictured (Fig. 1) is a snapshot of the si
%K branching
%K mammary
%K morphogenesis
%K stroma
%K TGF-¦Â
%U http://breast-cancer-research.com/content/3/4/218