Human chorionic gonadotropin as an angiogenic factor in breast cancer during pregnancy

Breast cancer associated with pregnancy is defined as the one in which the diagnosis is made in a pregnancy or within one year of delivery. Breast cancer is the second most common malignancy during pregnancy and it is generally considered to have a worse prognosis than the one that is not associated with pregnancy. The average patient is between 32 and 38 years of age. Steroid hormone receptor-positive cell populations comprise 80% of breast cancers, however, estrogen receptor levels in pregnancy-associated tumors are often low or absent. Extensive laboratory data suggest that angiogenesis plays an essential role in breast cancer development, invasion, and metastasis. One of the most powerful stimulatory factors, vascular endothelial growth factor (VEGF), functions in autocrine/paracrine pathways. Current research, generally has validated the poor prognosis and early relapse that are associated with increasing microvessel density, which is related to VEGF expression in tumoral cells. During pregnancy, human chorionic gonadotropin (hCG) induces neovascularization in various tissues, one of them being the placenta. Its receptors have been detected in epithelial cells in breast carcinoma tissue, and breast cancer cell lines. According to this premise the hCG normally produced during pregnancy could induce the synthesis of VEGF and by this means stimulate the development and metastatic potential of breast cancer cells in the pregnancy period. Thus, research involving hCG and VEGF would help us understand the physiopathology of breast cancer during pregnancy, as well as provide us with probable prognostic tools.