IGF1 and breast carcinoma: Although high levels of estrogen, IGF-1 and other cell division stimulators in pregnancy can lead to the stimulation of breast cell proliferation and are a precursor to the initiation and progression towards breast cancer, high levels of HCG and alpha-phytoprotein in pregnancy can have a protective role against breast cancer by increasing apoptosis, inhibiting cell division and enhancing differentiation, and this protective role is often greater in the first pregnancy [34–37].