The risk of breast cancer has been shown to increase immediately following pregnancy. Breast cancers that occur in the post-partum period are more aggressive, more likely to metastasize and are associated with worse patient outcomes. They also tend to affect younger women, and may represent a substantial proportion of early onset breast cancer, a phenomenon that disproportionately affects racial and ethnic minority groups, such as Hispanics. Hispanic women are more likely to have higher parity, are diagnosed with breast cancer at a younger age, and have a worse survival after diagnosis. The goal of this study, therefore, is to compare breast cancers diagnosed in Hispanic women in the high-risk post-partum period with those diagnosed outside of this time period to identify epigenetic features associated with the aggressive post-partum cancer. RNA and DNA were isolated from formalin-fixed, paraffin-embedded (FFPE) breast cancer tissues from a Hispanic population within the Ella Binational Breast Cancer study participants. Using a quantitative real-time reverse transcriptase approach (Exiqon miRCURY LNA™ Universal RT microRNA PCR panels), we were able to test for the expression of 360 human microRNAs (miRNAs) that our laboratory previously identified as miRNAs that are specific for human mammary cells. MiRNAs are short-stranded, non-coding RNAs that are often deregulated in breast cancer. We have identified seven miRNAs that are differentially expressed in breast cancer that occurs in the post-partum period including: hsa-miR-137, hsa-miR-31, hsa-miR-342-3p, hsa-miR-342-5p, hsa-miR-542-5p, hsa-miR-190b, and hsa-miR-103. Previously, our laboratory showed that epigenetic modifications, such as DNA methylation, deregulate miRNA expression in breast cancer. Consequently, we used a Sequenom MassARRAY platform to determine whether these miRNAs are also being epigenetically regulated. We are also investigating the mechanistic role these miRNAs may play in the early onset post-partum breast cancers.

Citation Format: Jose L. Munoz-Rodriguez, Lukas Vrba, Chengcheng Hu, Patricia A. Thompson-Carino, Maria Elena Martinez, Bernard W. Futscher. Epigenetic changes in postpartum breast cancer amongst Hispanic women. [abstract]. In: Proceedings of the Sixth AACR Conference: The Science of Cancer Health Disparities; Dec 6–9, 2013; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2014;23(11 Suppl):Abstract nr C74. doi:10.1158/1538-7755.DISP13-C74

©2014 American Association for Cancer Research.
2014