DNA methylation signatures of breast cancer in peripheral T-cells

Abstract

Background: Immune surveillance acts as a defense mechanism in cancer, and its disruption is involved in cancer progression. DNA methylation reflects the phenotypic identity of cells and recent data suggested that DNA methylation profiles of T cells and peripheral blood mononuclear cells (PBMC) are altered in cancer progression. Methods: We enrolled 19 females with stage 1 and 2, nine with stage 3 and 4 and 9 age matched healthy women. T cells were isolated from peripheral blood and extracted DNA was subjected to Illumina 450 K DNA methylation array analysis. Raw data was analyzed by BMIQ, ChAMP and ComBat followed by validation of identified genes by pyrosequencing. Results: Analysis of data revealed ~10,000 sites that correlated with breast cancer progression and established a list of 89 CG sites that were highly correlated (p<0.01, r>0.7, r