Circulating estradiol defines the tumor phenotype in menopausal breast cancer patients.

OBJECTIVE To correlate circulating hormone levels with the clinical and biological features of the tumors in menopausal breast cancer patients. DESIGN Circulating hormone levels were measured in 161 previously untreated menopausal breast cancer patients within 72 h of their planned surgery. The obtained hormone levels were correlated with tumor size, histological and nuclear grade, histological score, axillary nodal status, DNA-ploidy and Ki67-, c-erb-B2-, p53, Bax-, VEGF- and Nup88-expression. RESULTS The only statistically significant correlations found between circulating hormone levels and all tested variables were an inverse one between estradiol and the expression of the apoptosis-associated Bax gene (p=0.009), and again an inverse correlation between estradiol and the expression of c-erb-B2 (p=0.04). When comparing hormone levels with each other, a significant correlation between estradiol and progesterone (p<0.0001), an inverse one between estradiol and FSH (p=0.04) and a direct one between LH and prolactin (p=0.001) were found. CONCLUSION Higher circulating estradiol levels in postmenopausal breast cancer patients are associated with molecular features usually defining a biologically less aggressive tumor phenotype.