Proliferation of breast epithelial cells in healthy women during the menstrual cycle

Background Parenchymal Enhancement on Baseline Screening Breast MRI: Impact on Biopsy Rate and Short-Interval Follow-Up

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in the breast parenchyma during the menstrual cycle [4][5][6]. Estrogen has been shown to exert a histamine-like effect that causes an increase in microvascular permeability and vasodilation, and progesterone exerts a mitogenic effect that may increase metabolic activity, also resulting in an increase in perfusion [7,8].

The detection of malignancy at MRI is based on the fact that tumors show neovascularity, with increased blood flow and increased vascular leakiness, and relies on the differential enhancement between neoplastic tissue and normal breast parenchyma [9][10][11][12][13].

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“…in the breast parenchyma during the menstrual cycle [4][5][6]. Estrogen has been shown to exert a histamine-like effect that causes an increase in microvascular permeability and vasodilation, and progesterone exerts a mitogenic effect that may increase metabolic activity, also resulting in an increase in perfusion [7,8].…”

Challenges to defining a role for progesterone in breast cancer

“…During the menstrual cycle, MEC undergo sequential waves of proliferation and apoptosis. Notably, in primates (macaques and humans) increased terminal duct lobular unit cell proliferation coincides with the peak of serum progesterone that occurs during the luteal phase [13,[56][57][58], again suggesting a paracrine mechanism for this hormone in adult tissues. Upregulation of local IGF-1 may be a cooperating factor in this regard [59].…”

Breast-tissue sampling for risk assessment and prevention

“…Proliferation in terminal lobular duct units varies with age, menopausal status and phase of menstrual cycle; and is highest for premenopausal women in the luteal phase of the cycle (Soderqvist et al 1997, Potten et al 1998. In the normal breast epithelium, proliferation, as measured by Ki-67, is positively correlated with serum progesterone levels but not serum estradiol, prolactin, bioavailable testosterone, androstenedione or IGF-I (Soderqvist et al 1997). For premenopausal women, the proportion of normal breast epithelial cells expressing Ki-67 expression has been reported as approximately 1% in the follicular phase and 2-3% in the luteal phase (Soderqvist et al 1997, Shoker et al 1999.…”

“…In the normal breast epithelium, proliferation, as measured by Ki-67, is positively correlated with serum progesterone levels but not serum estradiol, prolactin, bioavailable testosterone, androstenedione or IGF-I (Soderqvist et al 1997). For premenopausal women, the proportion of normal breast epithelial cells expressing Ki-67 expression has been reported as approximately 1% in the follicular phase and 2-3% in the luteal phase (Soderqvist et al 1997, Shoker et al 1999. For postmenopausal women, the proportion of breast epithelial cells expressing Ki-67 is less than 1% (Shoker et al 1999).…”