Clinical significance of expression of estrogen receptor alpha and beta mRNAs in ovarian cancers

Novel human estrogen receptor (ER)-beta was identified in cDNA libraries from human testis. ER-beta specifically expresses in testis, ovary, thymus, spleen, osteoblasts and fetus. ER-beta might not conserve the same physiological functions as does ER-alpha. Therefore, the clinical significance of the expression of ER-alpha and ER-beta mRNAs in ovarian cancers was investigated. The percentage of ER-beta mRNA to ER-alpha mRNA ranged from 1.5 to 10% in normal ovaries. On the other hand, the ratios of ER-beta mRNA to ER-alpha mRNA were in a wide range in ovarian cancers. There was no significant difference in the ratios among ovarian cancers classified according to histological types or clinical stages. In a 48-month survival rate, the patient prognosis in ovarian cancers with a low or high ratio of ER-beta mRNA to ER-alpha mRNA (<1.5 or >10% of ER-beta mRNA to ER-alpha mRNA) was significantly worse than that in ovarian cancers with a medium ratio (>==1.5 to <==10% of ER-beta mRNA to ER-alpha mRNA). In conclusion, the intact synchronized expression of ER-beta mRNA interacting with ER-alpha mRNA might be damaged in some ovarian cancers, which might lead to poor patient prognosis.