BackgroundTumor expression of estrogen receptor (ER) is an important marker of prognosis, and is predictive of response to endocrine therapy in breast cancer. Several studies have observed that epigenetic events, such methylation of cytosines and deacetylation of histones, are involved in the complex mechanisms that regulate promoter transcription. However, the exact interplay of these factors in transcription activity is not well understood. In this study, we explored the relationship between ER expression status in tumor tissue samples and the methylation of the 5′ CpG promoter region of the estrogen receptor gene (ESR1) isolated from free circulating DNA (fcDNA) in plasma samples from breast cancer patients.MethodsPatients (n = 110) with non-metastatic breast cancer had analyses performed of ER expression (luminal phenotype in tumor tissue, by immunohistochemistry method), and the ESR1-DNA methylation status (fcDNA in plasma, by quantitative methylation specific PCR technique).ResultsOur results showed a significant association between presence of methylated ESR1 in patients with breast cancer and ER negative status in the tumor tissue (p = 0.0179). There was a trend towards a higher probability of ESR1-methylation in those phenotypes with poor prognosis i.e. 80% of triple negative patients, 60% of HER2 patients, compared to 28% and 5.9% of patients with better prognosis such as luminal A and luminal B, respectively.ConclusionSilencing, by methylation, of the promoter region of the ESR1 affects the expression of the estrogen receptor protein in tumors of breast cancer patients; high methylation of ESR1-DNA is associated with estrogen receptor negative status which, in turn, may be implicated in the patient’s resistance to hormonal treatment in breast cancer. As such, epigenetic markers in plasma may be of interest as new targets for anticancer therapy, especially with respect to endocrine treatment.

Background: 14-3-3sigma is an epithelial marker whose expression is induced by DNA damage through a p53-dependent pathway. 14-3-3sigma functions sequesters cyclin B1-CDC2 complexes outside the nucleus and thereby contributes to a G2 arrest. Epigenetic silencing by CpG methylation, p53 inactivation, and proteasome-dependent proteolysis leads to loss of 14-3-3sigma and is often observed in precancerous lesions and likely to be causally linked to the onset of cancer Objetive: To correlation methylation levels of promoter 14-3-3 sigma with association prognostic factors in breast cancer and their correlation with phenotype luminal. Material and Methods: This is a prospective study we quantified methylation levels of promoter 14-3-3 sigma gene in 107 women with breast cancer and 108 control subjects by Real Time QMS-PCR SYBR green (methylation-specific PCR) and analyzed association with prognostics factor in breast cancer. Results: Median age was 58 years (32-88); 69% were postmenopausal women. Nodal involvement N0; 63%,N1;30%,N2;7%), tumor size (T1;58%,T2;35%,T3;4%,T4;4%) and grade G1; 20%,G2;37%,G3;30%). Significant differences between breast cancer patients (pts) and healthy controls in relative serum levels of methylated gene promoters 14-3-3s (p=0.0047) were detected. Presence of methylated 14-3-3-s in serum of breast cancer patients was associated with T3-4 stage (OMS) (p<0.05) and nodal positive status (p< 0.05). With a median follow up 6 years we saw more probability of developing distance metastasis in patients with methylation 14-3-3 sigma (p>0.05). Conclusions: Hypermethylation of the 14-3-3 sigma promoter is an early and frequent event in breast neoplastic transformation, leading to the suggestion that silencing of 14-3-3 sigma may be an important event in tumor progression and particularly in breast carcinogenesis. This study identifies the presence of variations in global levels of methylation promoters genes in patients breast cancer with different phenotype classes and shows that these differences have clinical significance. Perhaps in the detection of CpG methylation of 14-3-3sigma may be used for diagnostic and prognostic purposes. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-05-06.

Background: Expression of 14-3-3 sigma is induced in response to DNA damage, and causes cells to arrest in G(2). Hypermethylation of CpG islands located in the promoter regions of tumor suppressor genes is now firmly established as an important mechanism for gene inactivation. Objetive: To study the relation of 14-3-3 sigma gene promoter hypermethylation and its transcription expression levels in sporadic breast carcinogenesis. Material and Methods:This is a prospective study we quantified methylation levels of promoter 14-3-3 gene in 107 women with breast cancer and 108 control subjects by Real Time QMS-PCR SYBR green and analyzed association with prognostics factor in breast cancer. Results: Median age was 58 years (32-88); 69% were postmenopausal women. Nodal involvement N0; 63%, N1;30%, N2;7%), tumor size (T1;58%, T2;35%, T3;4%, T4;4%) and grade G1; 20%, G2;37%, G3;30%). The methylation of 14-3-3σ were 60% of sporadic breast cancer patients and were 34% of normal breast (p=0.0047). The methylation of 14-3-3σ gene in serum was markedly related with T3-4 stage (p<0.05), nodal positive status (p<0.05) and poor outcome. With a median follow up 6 years we saw more probability of developing distance metastasis in patients with methylation 14-3-3σ (p>0.05). Conclusions: The recent identification of novel 14-3-3sigma-associated proteins by a targeted proteomics approach implies that 14-3-3sigma regulates diverse cellular processes, which may become deregulated after silencing of 14-3-3sigma expression in cancer cells. Therefore, it is possible that loss of σ expression contributes to malignant transformation by impairing the G2 cell cycle checkpoint function, thus allowing an accumulation of genetic defects. Perhaps in the detection of CpG methylation of 14-3-3σ may be used for diagnostic and prognostic purposes Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr B82.

224 Background: To determine whether Estrogen Receptor (ESR1) (+) and ESR1(-) status relates to epigenetic changes in breast cancer-related genes and to correlate with molecular breast cancer subtypes. Methods: Since January/02 to June/05, we quantified methylation levels ERS1 gene in serum of 92 pts breast cancer. A PCR quantitative technique was used to analyze levels of methylation gene. We also examined and correlationed the expression of ESR1 in tumors by immunohistochemistry with molecular phenotype. Results: Median age was 58 years (32-88); 69% were postmenopausal women. Nodal involvement (N0; 63%, N1; 30%, N2; 7%), tumor size (T1; 58%, T2; 35%, T3; 4%, T4; 4%) and grade (G1; 20%, G2; 37%, G3; 30%). Of the cases, 37 pts (40%) were Luminal A (LA), 32 pts (33%) Luminal B (LB), 14 pts (15%) Triple-negative (TN) and 9pts (10%) HER2+. The methylated ESR1 in serum was significantly associated with ESR1(-) in breast tumors >80% (p=0.0179). Methylation ESR1 was preferably associated with TN (80%) and HER2+ (60%) subtype. Nevertheless unmethylation ESR1 was found more frequently in LA (71%) and LB (59%) phenotype. With a median follow up of 5 years, we found worse overall survival (OS) with more frequent ESR1 methylation gene (p>0.05), Luminal A; ESR1 Methylation OS at 5 years 81% vs 93% when was ESR1 Unmethylation. Luminal B; ESR1 Methylation 86% SG at 5 years vs 92% in Unmethylation ESR1. Triple negative; ESR1 Methylation SG at 5 years 75% vs 80% in unmethylation ESR1. HER2; ESR1 Methylation SG at 5 years was 66.7% vs 75% unmethylation ESR1. Conclusions: Gene promoter region hypermethylation is a significant event in primary breast cancer. However, its impact on tumor progression and potential predictive implications remain relatively unknown. Our study identifies the presence of variations in global levels of methylation promoters ESR1 genes in breast cancer with different phenotype classes and shows that these differences have clinical significance. Although numerous issues remain to be resolved, quantitative measurement of circulating methylated DNA may be of significance in the assessment and search of targeted therapy resistance related to ESR1 and HER2 status by epigenetic or transcriptional cancer therapy.