Cancer Research UK Cambridge Research Institute, Li Ka Shing Centre, Robinson Way, Cambridge, UK.
Horm Cancer. 2011 Apr;2(2):85-90. doi: 10.1007/s12672-010-0055-1. Epub 2010 Dec 16.
There is emerging evidence that the mammary epithelium in both mice and humans is arranged as a hierarchy that spans from stem cells to differentiated hormone-sensing, milk-producing and myoepithelial cells. It is well established that estrogen is an important mediator of mammary gland morphogenesis and exposure to this hormone is associated with increased breast cancer risk. Yet surprisingly, the primitive cells of the mammary epithelium do not express the estrogen receptor-α (ERα) or the progesterone receptor. This article will review the mammary epithelial cell hierarchy, possible cells of origin of different types of breast tumors, and the potential mechanisms on how estrogen and progesterone may influence the different subcomponents in normal development and in cancer. Also presented are some hypothetical scenarios on how this underlying biology may be reflected in the behavior of ERα(+) and ERα(-) breast tumors.
越来越多的证据表明，无论是在小鼠还是人类中，乳腺上皮组织都呈现出一种从干细胞到分化的激素感应、产奶和肌上皮细胞的层级结构。雌激素是乳腺形态发生的重要介质，这一点已经得到充分证实，而接触这种激素与乳腺癌风险的增加有关。然而令人惊讶的是，乳腺上皮的原始细胞并不表达雌激素受体-α（ERα）或孕激素受体。本文将回顾乳腺上皮细胞层级结构、不同类型乳腺癌的可能起源细胞，以及雌激素和孕激素如何影响正常发育和癌症中不同亚成分的潜在机制。还提出了一些假设性的情景，说明这种潜在的生物学可能如何反映在 ERα（+）和 ERα（-）乳腺癌的行为中。
