45P - Methylation of DNA free in blood sample as prognostic factor in breast cancer subtype

Date 08 May 2014
Event IMPAKT 2014
Session Welcome reception and Poster Walk
Topics Breast Cancer
Translational Research
Presenter Joaquina Martinez-Galan
Citation Annals of Oncology (2014) 25 (suppl_1): i8-i16. 10.1093/annonc/mdu066
Authors J. Martinez-Galan, C. González-Rivas, J.R. Delgado
  • Medical Oncology, Hospital Universitario Virgen de las Nieves, 18014 - Granada/ES

Abstract

Background:

The impact of methylation as a factor on tumor progression and its potential predictive value remain relatively unknown. The aim of this study was to correlate methylation levels of promoter ESR1 with association to known prognostic factors in breast cancer and their correlation with expression of estrogen receptor (ER) in tumor and luminal phenotype.

Material and methods:

We quantified methylation levels of promoter ESR1 gene in 107 patients with breast cancer by real time PCR (methylation-specific PCR). Tumors were classified as phenotype basal, luminal A, luminal B and Her2+.

Results:

An inverse correlation between aberrant methylation in promoter region ESR1 and ER expression was observed in breast cancer cells. The presence of methylation ESR1 in serum of breast cancer patients was associated with ER-negative phenotype tumoral (p = 0.0179). We observed that methylated ESR1 was preferably associated with triple negative and HER2 + phenotype, and worse interval progression free survival and overall survival p < 0.05.

Conclusion:

This study identified the presence of variations in global levels of methylation in promoters of genes in breast cancer with different phenotype subtype and show that these differences have clinical significance. These showed that frequent methylation had a strong association with molecular phenotype of breast cancer and perhaps in the future can explain therapy resistance related to ER and HER2+ status in breast cancer patients.

Disclosure:

All authors have declared no conflicts of interest.