The development of this research project was based on knowledge generated in a pilot study phase I trial for testing the inhibitory effects or recombinant hCG (rhCG) on primary breast cancer. This Trial was done in collaboration with Dr. Jaak Ph. Janssens, from the University of Hasselt, in collaboration with the H. Hart Hospital, Tienen, and the Ziekenhuis Oost-Limburg, Genk, in Belgium. In this phase 1 clinical trial 25 postmenopausal women with newly diagnosed breast cancers of more than 1.5 cm were biopsied before randomization to receive either 500 µg rhCG (n=20) or a placebo. After 2 weeks, surgery was done and tissues were analyzed with regard to morphological, immunohistochemical and biochemical changes in tissues and plasma. rhCG significantly reduces the proliferative index and the expression of both the estrogen and progesterone receptors. rhCG does not modify the hormonal level of estradiol, progesterone, inhibin and follicle stimulating hormone (FSH) but increases significantly the level of leutinizing hormone (LH). In a second pilot study, clinical efficacy was tested through an open-label single centre study in 13 postmenopausal women with metastatic breast cancer. 500 µg rhCG administered once every two days shows activity in postmenopausal metastatic breast cancer. The time to progression is relatively short. Response to previous hormonal treatment is indicative of rhCG activity. Given the data in primary and metastatic breast cancer, further large scale investigation of rhCG is highly warranted. rhCG can be an realistic option in prevention trials.
A second clinical trial similar to the one performed in Belgium has been conducted in collaboration with Dr. Ismael Silva of the Federal University at Sao Paulo, Brazil. In this protocol, normal and tumor tissues have been obtained before and after hCG treatment.
Based on these studies an NCI sponsored trial has been initiated in our laboratory. This research project proposes to test the hypothesis that the genomic profile of breast epithelial cells of asymptomatic nulliparous women who are carriers of BRCA1 germline mutations are characteristic of such risk, and that the induction of differentiation by treatment with human chorionic gonadotropin (r-hCG) would revert the “high risk” to a “low risk” signature that would serve as a biomarker indicative of decreased breast cancer risk. This hypothesis is supported by the observations that pregnancy and breastfeeding reduce the risk of both sporadic and BRCA1-associated breast cancer, and that treatment with the placental hormone hCG confers a similar degree of protection in experimental models. Because the lifetime breast cancer risk of BRCA1 mutation carriers is increased by 85%, tumors arise in them at a significantly lower age than sporadic cancers, and in addition they are unresponsive to endocrine and immunotherapy due to their negativity for estrogen receptor alpha (ERa), progesterone receptor (PR), and Her2, factors that worsen their prognosis, this high risk population is an ideal target for implementing preventive measures based on the use of r-hCG as a chemopreventive agent. This approach is supported by our demonstration that the complete differentiation of the breast induced by pregnancy is one of the main mechanisms that confer protection to both women and rodents, in which treatment of virgin rats with hCG prevents the initiation and progression of chemically induced mammary cancer. Furthermore, we have demonstrated that the differentiation of the breast imprints a specific genomic signature that is characteristic of parous women and could therefore serve as a biomarker indicative of the lifetime decreased breast cancer risk. In this exploratory application we are aiming at establishing the proof of principle that treatment of “high breast cancer risk” women with recombinant human chorionic gonadotropin (r-hCG) will change their breast epithelium’s high risk genomic profile to one similar to that identified in women with a history of early full first term pregnancy. For this purpose, breast epithelial cells will be collected by random periareolar fine needle aspiration (RPFNA) from 18 women carriers of BRCA1 deleterious mutations. Cells will be cytopathologically evaluated, RNA will be extracted for analysis of gene expression by cDNA microarray, and immunocytochemical determination of cell proliferation by Ki67, ER and PR status, parameters will serve as a baseline of the “high risk” genomic profile. We propose to test whether a 90 day (3-month) treatment with r-hCG will activate or downregulate genes related to immune surveillance, DNA repair, programmed cell death, transcription, and chromatin structure/activators/co activators in comparison with the pre-treatment genomic profile, changes that will indicate that the “high risk” has been converted to a “low risk” risk genomic signature, such as that found in women with a history of early first full term pregnancy. This knowledge will serve as the basis for establishing novel genomic signatures as intermediate biomarkers for larger preventive clinical trials at the completion of this project.