Methylation Profile of ER and HER2 negative (ER-/Her2-) breast tumors.

BRANHAM, MARÍA; MARZESE, DIEGO; GAGO, FRANCISCO; OROZCO, JAVIER; TELLO, OLGA; ROQUÉ, MARÍA; VARGAS ROIG, LAURA

Chicago, Illinois

Congreso; American Society of Clinical Oncology (ASCO) Annual Meeting.; 2011

ASCO

Background: Breast cancer is a collection of clinically, histopathologically and molecularly heterogeneous diseases, with diverse outcomes and responses to treatment. ER-/HER2- is an immunohistochemical description of breast cancers with a double negative staining for ER and HER2. These tumors have an aggressive clinical behavior and poor prognosis. The hypermethylation of CpG islands (CpGI) is a common epigenetic alteration for suppressing gene expression in breast cancer. Understanding how these epigenetic changes are involved in tumor progression is important for a better comprehension of tumor biology. Here we evaluated the methylation status of ER-/HER2- compared to luminal breast tumors. Methods: For the methylation analysis, we used the methyl specific-multiplex ligation probe amplification assay. Seventy invasive ductal carcinomas (IDC) were included in the study. In 20 IDCs we analyzed 127 CpGI and in 50 IDCs we analyzed 49 CpGI. Results: Among the islands studied we found positive association between ER-/HER2- tumors and methylated MGMT (p