Associations of the serum antibodies to estradiol and the tumor estrogen receptors at the breast cancer patients

Serum antibodies, specific to estradiol (IgG-Es1) and corresponding antiidiotypic antibodies (IgG-Es2) at 103 healthy women (HW) and 273 breast cancer patients (BCP) were investigated. Simultaneously high levels of IgG-Es1 and IgG-Es2 were revealed at the ER+PR+ BCP (34,6%) and ER + PR- (39,0%), but not at the ER-PR- BCP (18,2%) and HW (18,4%). High ratio IgG- Es1/IgG-Es2, but not IgG-Es1 and IgG-Es2 separately were associated with high concentration of serum estradiol (Es) at ER+ but not ER-BCP. It was supposed that IgG-Es1 could stimulate ER + + BC by increasing Es concentration and IgG-Es2 by binding to membrane estrogen receptors. Immunoanalysis of serum IgG-Es1 with IgG-Es2 was recommended for ER+ BC risk valuation and preventative therapies by selective ER modulators.