Estrogen Receptor Expression In Breast Cancer Research Articles

Validation of a five reagent immunohistochemistry assay for prognostication of estrogen-receptor expressing breast cancer

10081 Background: We have previously reported the translation of gene expression data into a five reagent polyclonal antibody immunohistochemistry assay targeting p53, SLC7A5, NDRG1, HTF9C, and CEACAM5 whose staining results are combined using a Cox proportional hazard model for prognostication of estrogen receptor expressing breast cancer. Monoclonal antibodies targeting these genes have now been obtained and or produced. Methods: Paraffin blocks from 229 patients seen at the University of Alabama at Birmingham Clinical Cancer Center were assembled into tissue arrays and clinical follow-up data was collected by chart review. Immunohistochemical stains were performed and cases scored as positive or negative with the five monoclonal antibody assay. In order to further test the assays predictive value for assessing outcome, the prospectively defined Cox proportional hazard model and high, moderate, and low risk cutoffs were applied to the staining results on the estrogen receptor positive (ER+) patients for whom a assessment of death due to disease (DOD) and staining results for all five biomarkers were available. Results: The Kaplan-Meier estimates of outcome confirmed that the Cox model distinguished ER+ patients with poor outcomes. The five antisera algorithm identified high risk patients with a five year estimate of DOD of 41% compared to 20% for moderate and 9% for good (p=0.006) (79 patients total). In ER+ node negative patients the model identified high risk patients with a five year estimate of DOD of 50% compared to 18% for moderate and 5% for good (p=0.01) (40 patients total). The prognosticator was independent of age, pathological stage, and tumor size. Conclusions: A panel of five antibodies can significantly improve upon traditional prognosticators in predicting outcome for estrogen receptor positive breast cancer patients. This represents the third independent validation study performed on cohorts from different institutions. Retrospective studies on clinical trial cohorts and prospective studies should be performed to further establish the utility of this test in identifying early stage breast cancer patients at high risk for recurrence. [Table: see text]

Breast cancer risk associated with genotypic polymorphism of the genes involved in the estrogen-receptor-signaling pathway: a multigenic study on cancer susceptibility

The reproductive hormone, estrogen, contributes to the development of breast cancer by binding to the estrogen receptor (ER) in the nucleus, triggering cell growth and tumor promotion. In addition to its role in regulating target genes and signaling pathways involved in cell cycle progression, the ER-signaling pathway may regulate the expression of chromatin-remodeling gene, Metastasis-associated 3 (MTA3), or interact with chromatin-remodeling protein, Metastasis-associated 1 (MTA1). The invasion-suppressor gene, E-Cadherin (E-Cad), has recently been identified as a downstream target gene regulated by the ER-MTA3 pathway via the transcriptional repressor, Snail, and the ER-MTA3-Snail-E-Cad pathway has therefore been evoked to explain the clinical observation that ER expression in breast cancer is generally associated with a better clinical outcome. Since E-Cad may play an initiating role during breast tumorigenesis, we hypothesized that this ER-signaling pathway may also determine susceptibility to breast cancer, and examined this in a multigenic case-control study of 468 incident breast cancer patients and 470 healthy controls by genotyping the single nucleotide polymorphisms (SNPs) in five genes (ER, MTA3, Snail, E-Cad, and MTA1) in the ER-signaling pathways. Support for this hypothesis came from the observations that (a) with the exception of Snail, which interacted differently with reproductive risk factors in relation to breast cancer risk, there was a joint effect of the SNPs of these genes and estrogen-related risk factors (age at first full-term pregnancy and obesity, measured by the body mass index) on breast cancer risk (p < 0.05); (b) a trend toward increased risk of developing breast cancer was seen in women harboring a greater number of putative high-risk genotypes of these genes in ER-signaling pathways; (c) this association between risk and the number of putative high-risk genotypes was stronger and more significant in women thought to have experienced higher estrogen level, i.e., obese women; and (d) the risk effect conferred by obesity was only significant in women with a higher number of putative high-risk genotypes of the ER-signaling genes. These epidemiological findings highlight the role of newly identified novel ER-related pathways in breast cancer development and provide a more comprehensive picture of the tumorigenic effect of estrogen in breast cancer development.

Restoration of Transforming Growth Factor-β Signaling through Receptor RI Induction by Histone Deacetylase Activity Inhibition in Breast Cancer Cells

The loss of transforming growth factor-beta (TGF-beta) response due to the dysregulation of TGF-beta receptors type I (RI) and type II (RII) is well known for its contribution to oncogenesis. Estrogen receptor-expressing breast cancer cells are refractory to TGF-beta-mediated growth control because of the reduced expression of TGF-beta receptors. Although RII is required for the binding of TGF-beta to RI, RI is responsible for directly transducing TGF-beta signals through the Smad protein family. Treatment of estrogen receptor-expressing MCF-7L and ZR75 breast cancer cells with the histone deacetylase (HDAC) inhibitor suberoylanilide hydroxamic acid (SAHA) led to a dramatic induction of RI. Accumulation of acetylated histones H3 and H4 was observed in the SAHA-treated cells. Chromatin immunoprecipitation analysis followed by PCR with RI promoter-specific primers indicated an accumulation of acetylated histones in chromatin associated with the RI gene, suggesting that histone deacetylation was involved in the transcriptional inactivation of RI. SAHA treatment stimulated RI promoter activity through the inhibition of Sp1/Sp3-associated HDAC activity. Histone acetyltransferase p300 stimulated RI promoter activity, thus further confirming the involvement of HDAC activity in the transcriptional repression of RI. Significantly, SAHA-mediated RI regeneration restored the TGF-beta response in breast cancer cells.

Abortion and the NHS.

<b>1059</b> <h3><b>Objectives:</b></h3> Estrogen receptor (ER) expressing tumor show better prognosis due to responsiveness to anti-estrogen treatment. Tamoxifen is an FDA approved anti-estrogenic drug. Radiolabelling of tamoxifen with Tc-99m and Re-188 as a potential theranostic pair for ER expressing breast cancer patients. <h3><b>Methods:</b></h3> Tc-99m and Re-188 tricarbonyls were synthesized in house using sodium boranocarbonate as in situ carbon monoxide producing source. For Re-188 tricarbonyls borane ammonia and phosphoric acid were also added. Tamoxifen was radiolabelled via Tc-99m and Re-188 tricarbonyl core. QC was performed and complexes were also characterised by MALDI-TOF and NMR. In-vitro receptor binding and blocking studies were performed in cell lines (MCF-7, MDA-MB-231) with Tc-99m tricarbonyl tamoxifen. MTT assay was done to assess cytotoxicity of Re-188 tricarbonyl tamoxifen. Biodistribution studies were performed in female wistar albino rats with Tc-99m tricarbonyl tamoxifen. Patient imaging was done after obtaining ethical clearance from the institute. Four histopathological proven ER expressing patients were recruited and F-18 FDG PET/CT was performed. The whole body and SPECT/CT were acquired after injection of Tc-99m tricarbonyl tamoxifen (8-14 mCi) and the scans were compared with F-18 FDG PET/CT for tracer uptake in the lesion/s <h3><b>Results:</b></h3> Tc-99m and Re-188 tricarbonyl and Tc-99m and Re-188 tricarbonyl tamoxifen were synthesized with high radiolabelling efficiency (&gt;99%). The formulations were found sterile and apyrogenic. In mass spectra, a major peak corresponding to the sum of molecular weights of Tc-99m/Re-188 tricarbonyl and tamoxifen (M+H)⁺indicated good radiolabelling. The chemical shift observed in the protons of α9-CH₂and β9-CH₂and N(CH₃)₂in NMR spectra of Re-188 and Tc-99m tricarbonyl tamoxifen suggested binding of Tc-99m/Re-188 tricarbonyl near aliphatic side chain of tamoxifen. Maximum 30% binding was observed in estrogen expressing MCF-7 cell line with respect to ~3% binding with non estrogen expressing MDA-MB-231. Receptor binding (%) was reduced to 8.4% when preincubated with excess tamoxifen. Re-188 tricarbonyl tamoxifen (40µCi, 2µg) showed 93.2% cytotoxicity on MCF-7 cells (5X10³). More than 90% cytotoxicity was observed with 1/20 times amount of tamoxifen in Re-188 tricarbonyl tamoxifen as compared to tamoxifen alone (20µg, 71.48%) and Re-188 alone (40µCi, 36.9%). In biodistribution study in rats, counts were noted in lung, liver, spleen and kidney. High blood counts were noted up to 2 hrs. In clinical study, Tc-99m tricarbonyl tamoxifen uptake was observed at primary site (breast) and lymph nodes in three patients. On comparison, Tc-99m tricarbonyl tamoxifen SPECT/CT findings were in concordance with F-18 FDG PET/CT. However, the low lesion to background contrast was observed with Tc-99m tricarbonyl tamoxifen. No uptake of Tc-99m tricarbonyl tamoxifen was seen in fourth patient, who was on tamoxifen therapy from last six months, probably due to receptor saturation However, lesions were visualised on F-18 FDG PET/CT image. <h3><b>Conclusions:</b></h3> Tc-99m tricarbonyl tamoxifen could be a potential diagnostic tool for ER expressing breast cancer patients in centres not having on site cyclotron facility. The radiopharmaceutical shows the therapeutic potential when Re-188 is used in lieu of Tc-99m.