Up-regulation of P13K/Akt Signaling by 17 beta-estradiol through Activation of Estrogen Receptor-alpha in Breast Cancer Cells / 한국유방암학회지

PURPOSE: Estrogen stimulates cell proliferation in breast cancer, the biological effects of which are mediated through two intracellular receptors: estrogen receptor-alpha (ERalpha) and estrogen receptor-beta (ERbeta). However, the actual role of ERs in the proliferative action of estrogen remains to be established. It was recently found that ER activates phosphatidylinositol-3-OH kinase (PI3K), via its binding with the p85 regulatory subunit of PI3K. Therefore, possible mechanisms may include ER-mediated phosphoinositide metabolism, with the subsequent formation of phosphatidylinositol-3, 4, 5-trisphosphate (PIP(3)), which is generated from phosphatidylinositol 4, 5-bisphosphate (PIP(2)) via PI3K activation. The present study has demonstrated that 17b-estradiol (E2) up-regulates PI3K in an ERalpha, but not an ERbeta dependent manner, and also stimulates cell growth in breast cancer cells. METHODS: To study this phenomenon, we treated ER-positive MCF-7 cells and ER-negative MDA-MB-231 cells with 10 nM E2. RESULTS: The treatment of MCF-7 cells with E2 resulted in a marked increase in the expression of PI3K (p85), which was paralleled by increases in the levels of phospho-Akt (Ser-473) and PIP3. These observations were also correlated with increased E2-induced cell proliferation activity. However, no effects of E2 on breast cancer cells were observed in the MDA-MB-231 cell line, indicating the pathway of E2-mediated up-regulation of PI3K/Akt is ERalpha-dependent. CONCLUSION: These results suggest that estrogen activates PI3K/Akt signaling via an ERalpha-dependent mechanism in MCF-7 cells.

A case of phyllodes tumor in a 10-year-old girl / 한국유방암학회지

A premenarcheal 10-year-old girl visited our clinic due to a rapidly growing and painless mass of the right breast of three months duration. The breast mass was removed using a wide local excision. The pathological findings revealed the tumor was made up of a phyllodes tumor. A phyllodes tumor, also known as cystosarcoma phyllodes, is a rare fibroepithelial tumor of the breast, which accounts for 0.3 to 1.0 % of all breast neoplasms. They have a greater degree of stromal cellularity than fibroadenomas, with a characteristic leaf-like projection. These tumors can occur between the ages of 9 to 88 years, but are most common in the third and fourth decades of life; therefore, are uncommon in children. A phyllodes tumor in an adolescent patient was first studied by Amerson, in 1970, at which time he reviewed 355 cases from the American literature, and found a five percent incidence in subjects below 20 years old. Because only a few cases have been reported in the literature; here we report a case of a phyllodes tumor in a 10-year-old girl.