Role of progesterone in the genesis of Breast Cancer-3

Progesterone and Migration of Breast Cancer Cells

Death from breast cancer is usually due to invasion and metastasis to distant target organs (e.g. brain, bone lungs). Progesterone and progestins stimulate breast cancer migration and invasion (Should we therefore gynaecologits stop prescribing Progesterone)??  The migration and invasion of cancer cells involve

complex mechanisms. The first step is reorganization of the cells actin/myosin cytoskeleton. This reorganization enables the cells to develop membrane protrusion (called filopodia and lamellipodia). These protrusions are involved in the cell’s ability to detach itself from the main tumor body and, to enter lymphatic vessels and migrate. There are several 17|3-estradiol up-regulating families of actin-binding pro­tein which leads to this phenomena . Studies comparing the specific effect of different synthetic progestins have demonstrated their individual and different effect on PR+ breast cancer cell migration and invasion in vitro. This activation is medi­ated in synergy with the activation of the actin-binding protein moesin to increase the formation of membranous structures. These specialized structures interact with the extra cellular matrix of nearby cells, allowing locomotion of the breast cells.. It has been suggested that an in vitro “invasion index” for the effect of specific progestins on breast cancer cells lines incubated in vitro, with the addition of each progestin, with or without estrogen in the media can indicate the different and variable effects of progestins