Click on image to view larger version.

Fig. 1. Hierarchical modeling of human breast function. Similarities between the
organization of human and mouse mammary glands have enabled observations in
one tissue to be transferred to the other. This dynamic exchange of
information has led to the gradual development of mammary gland models that
now represent a continuum of organotypic systems ranging in complexity from
monotypic 3D cultures to multicellular co-cultures to in vivo xenograft
models. Each of the 3D models depicted here represents a physiologically
relevant assay in its own right. However, when engineered with common cellular
components and used in series, these models become invaluable tools for the
identification and verification of disease-related molecules as well as for
the design and translation of effective drug therapies. Future in vivo models
that are more faithful to the human mammary microenvironment may be achieved
in a `humanized' mouse model in which mammary glands are entirely repopulated
by breast cell types of human origin. Ep, epithelial cell; Myoep,
myoepithelial cell. Adapted from previous publications
(Ronnov-Jessen et al., 1996;
Schmeichel et al., 1998).