Dual role of pregnancy in breast cancer risk.

Reproductive history is one of the strongest risk factors for breast cancer in women. Pregnancy can promote short-term breast cancer risk, but also reduce a woman's lifetime risk of breast cancer. Changes in hormone levels before and after pregnancy are one of the key factors in breast cancer risk. This article summarizes the changes in hormone levels before and after pregnancy, and the roles of hormones in mammary gland development and breast cancer progression. Other factors, such as changes in breast morphology and mammary gland differentiation, changes in the proportion of mammary stem cells (MaSCs), changes in the immune and inflammatory environment, and changes in lactation before and after pregnancy, also play key roles in the occurrence and development of breast cancer. This review discusses the dual effects and the potential mechanisms of pregnancy on breast cancer risk from the above aspects, which is helpful to understand the complexity of female breast cancer occurrence.

Antiproliferative effect of secofriedelanophyllemblicine, a triterpenoid present in the roots of Phyllanthus emblica L.

Phyllanthus emblica L. is a widely distributed tropical medicinal plant with good therapeutic properties. In the present study, the chemical constituents isolation of the roots of P. emblica were carried out and six known compounds (1-6) were purified and their structures were determined by means of spectroscopic analysis. The known triterpenoid, secofriedelanophyllemblicine (1), was selected to check for its cytotoxic effect on a series of human tumor cells and normal cells. Secofriedelanophyllemblicine exhibited cell growth inhibition specifically on MCF-7 breast cancer cells when compared to other tested cell lines. Further flow cytometric analysis showed that secofriedelanophyllemblicine could inhibit cell proliferation and induced G2 phase arrest in the cell-cycle progression of MCF-7 cells. The gathered results suggest that secofriedelanophyllemblicine is a cell-cycle regulator in MCF-7 human breast cancer cells and might be used as a candidate chemopreventive agent for breast cancer prevention and intervention.