All these data are consistent with E2 increasing production of TGFalpha in ER-positive ovarian cancer and this in turn acting through the EGF receptor to modulate growth in an autocrine manner.
Conversely, estrogen did not influence expression of BRCA1 in HBL-100 cells that lacked the estrogen receptor, although the constitutive levels of BRCA1 mRNA (but not protein) in these cells were 5- to 30-fold higher than in other breast and ovarian cancer cells.
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.
The identification of a second estrogen receptor gene (ERbeta), expressed predominantly in ovarian granulosa cells, led us to explore its possible role in ovarian cancer, particularly in granulosa cell tumors (GCT).
In addition, intracellular hK4 levels, as detected on Western blot analysis, were induced by 100 nM estrogen treatment of the estrogen receptor positive ovarian carcinoma cell line OVCAR-3, >8-24 h. Our results show that the level of KLK4 expression and expression of KLK4 mRNA variants are associated with progression of ovarian cancer, particularly late stage SER adenocarcinomas.
Here we report that the FR-alpha gene promoter is repressed in the presence of 17beta-estradiol and derepressed by the antiestrogens tamoxifen and ICI 182780 in a promoter-specific and ER-alpha-dependent manner in carcinoma cell lines including HeLa (cervical carcinoma), BG-1 (ovarian carcinoma), and IGROV-1 (ovarian carcinoma).
Although estrogen receptor was expressed in both the ovarian and breast cancers, genes that are coregulated with the estrogen receptor in breast cancers, including GATA-3, LIV-1, and X-box binding protein 1, did not show a similar pattern of coexpression in the ovarian cancers.
However, association analyses of two polymorphisms suggest that the ER-alpha gene or a gene located close to the ER-alpha locus might be related to susceptibility of familial ovarian cancer without BRCA1 mutation.
The top 20 differentially expressed genes included 10 genes (Spp1, Cyp1b1, Btg1, Cfh, Mt1, Mt2, Igfbp5, Gstm1, Gstm2, and Esr1) implicated in various aspects of ovarian carcinomas, and other 3 genes (Gsto1, Lcn7, and Alcam) associated to breast cancer.
To study a potential role of estrogen receptor-alpha gene amplification for estrogen receptor overexpression in ovarian cancer, a tumor tissue microarray containing 428 ovarian cancers was analyzed by fluorescence in situ hybridization for estrogen receptor-alpha gene amplification and immunohistochemistry for estrogen receptor expression.
Our results indicate that the determination of ESR1 levels by kinetic PCR may be superior to immunohistochemical methods in assessment of biologically relevant levels of ER expression in ovarian carcinoma, and is feasible in routinely used FFPE tissue.
In view of potential endocrine treatment options, we tested the role of ESR1 mRNA expression in ovarian cancer in the context of a neo-adjuvant chemotherapy trial.
A SNP 19 kb downstream of ESR1 (rs2295190, G-to-T change) was associated with invasive ovarian cancer risk, with a per-T-allele odds ratio (OR) of 1.24 [95% confidence interval (CI), 1.06-1.44, P = 0.006]. rs2295190 is a nonsynonymous coding SNP in a neighboring gene called spectrin repeat containing, nuclear envelope 1 (SYNE1), which is involved in nuclear organization and structural integrity, function of the Golgi apparatus, and cytokinesis.
Assessment of estrogen receptor (ER) expression by immunohistochemistry has yielded inconsistent results as a prognostic indicator in ovarian carcinoma.