Fig. 1

The adipocyte-containing tumor microenvironment (TME) in breast cancer (BC) tissue. A According to the distribution characteristics, adipose tissue (AT) can be cataloged into breast AT, subcutaneous AT, visceral AT, and intramuscular AT. B The adipocytes in breast AT (nBAs) represent a unique cell population to sustain the breast morphology. The main structure of the mammary gland consists of a system of acinus and lobules. C The TME in breast cancer consists of multiple adipocyte types, including ADSCs, pre-adipocytes, TSAs, and CAAs. Process of carcinoma in situ (CIS) and invasive carcinoma (IC) of the breast: the ducts consist of luminal cells (inner layer) and myoepithelial cells (outer layer), and are surrounded by the basement membrane, adipocytes, and other mesenchymal cells. CIS is characterized by tumor tissue distribution confined to epithelial cells, not breaking through the basement membrane, and not invading the interlobular space. Once the tumor cells have penetrated the basement membrane, invasive breast cancer occurs. At this point, breast cancer cells can interact with adipocytes at the invasion front, and educate them into CAAs to support breast cancer progression